Tag Archives: traffic calming

Transportation is Destiny: Design for Happy People, Not Happy Cars

by Dom Nozzi

The following is a summary of a talk I was invited to give at a PLAN-Boulder County forum on Friday, January 24. As a town and transportation planner, I cautioned Boulder not to put too much emphasis on easing car traffic flows—particularly by such conventional methods as adding a second turn lane at intersections or requiring a developer to provide too much car parking. I described the ingredients of a healthy, vibrant city, summarized how a seemingly beneficial city objective of reducing traffic congestion can often undermine important Boulder objectives, and offered a number of strategies that would help Boulder both properly manage transportation and promote its long-range goals.

A great city is compact, human scaled, has a slow speed center, and promotes gatherings of citizens that catalyze “synergistic interaction” (brilliant ideas and innovations, as the sum becomes greater than its parts). Most importantly, a quality city does exceptionally well in promoting “exchanges” of goods, services, and ideas, which is the most important role of a city, and is best promoted by the interaction that occurs through compact community design.

About 100 years ago, automakers, home builders, and oil companies (“the Sprawl Lobby”) started realizing that they could make lots of money by creating what has since become a self-perpetuating vicious cycle in communities. If communities could be convinced to ease the flow of car traffic by building enormous highways and parking lots (and subsidizing car travel by having everyone—not just motorists—pay for such roads, parking, and gasoline), huge amounts of money could be made selling cars, homes and gasoline. The process eventually was feeding on itself in a growing, self-perpetuating way, because the highways, parking and subsidies were forcing and otherwise encouraging a growing number of Americans to buy more and more cars, use more and more gasoline, and buy sprawling homes that were further and further from the town center. Why? Because the subsidized highways and gasoline were powerfully promoting community dispersal, high speeds, isolation, and an insatiable demand for larger highways and parking lots. Each of these factors were toxic to a city, led to government and household financial difficulties, destroyed in-town quality of life (which added to the desire to live in sprawl locations), and made travel by transit, bicycle or walking increasingly difficult and unlikely (an added inducement to buy more cars).

The inevitable result of the Sprawl Lobby efforts has been that cities throughout America are dying from the “Gigantism” disease.

The “Gigantism” Disease

One of the most important problems we face is that cars consume enormous amounts of space. On average, a person in a parked car takes up about 17 times more space than a person in a chair. And when moving, a motorist can take up to 100 times as much space as a person in a chair. Cities are Untitledseverely diminished by this level of wasteful use of land by cars—particularly in town centers (where space is so dear), and especially in communities such as Boulder, where land is so expensive.

Overemphasis on car travel breeds and spreads the gigantism “infection,” and promotes ruinously higher travel speeds. What happens when we combine the gigantism and high speeds with the “travel time budget” (humans tend to have a budget of about 1.1 hours of round-trip commuting travel each day)?

People demand larger highways and parking lots. Gigantic highways, overpasses, and asphalt seas of parking are necessary to accommodate the space-hogging, high-speed needs of the growing number of cars. This process dramatically increases the “habitat” for cars, and because such places are so utterly inhospitable to people, substantially shrinks the habitat for people.

Because it is so dangerous, unpleasant, and infeasible to travel on these monster highways by bicycle, walking, or transit (what economists call “The Barrier Effect”), an endlessly growing army of motorists and sprawl residents is thereby created, which, of course, is a financial bonanza for the Sprawl Lobby.

It is surprising and disappointing that Boulder has, on numerous occasions, shown symptoms of the gigantism disease (surprising because citizens and city staff are relatively well-informed on transportation issues). A leading concern in Boulder is the many intersections that have been expanded by installing double left turn lanes. Installing a single left turn lane historically resulted in a fair improvement in traffic flow, but when a second left turn lane is installed, intersections typically suffer from severely diminished returns. There is only a tiny increase in traffic accommodated (and often, this increase is short-lived) and this small benefit is offset by a huge required increase in walk time for crosswalks that are now very lengthy to cross on foot (which necessitates a very long “walk” phase for the crosswalk). Indeed, some traffic engineers or elected officials are so intolerant of the time-consuming long walk phase that many double-left turn intersections actually PROHIBIT pedestrian crossings by law.

These monster double left turn intersections destroy human scale and sense of place. They create a place-less, car-only intersection where walking and bicycling (and, indirectly, transit) trips are so difficult and unpleasant that more trips in the community are now by car, and less by walking, bicycling and transit. And those newly-induced car trips, despite the conventional wisdom, actually INCREASE greenhouse gas emissions (due to the induced increase in car trips).

Double left turn lanes (like big parking lots and five- or seven-lane highways) disperse housing, jobs, and shops in the community, as the intersection—at least briefly—is able to accommodate more regional car trips. Because the intersection has become so inhospitable, placeless and lacking in human scale, the double left turn repels any residences, shops, or offices from being located anywhere near the intersection, and thereby effectively prevents the intersection from ever evolving into a more walkable, compact, village-like setting.

The following chart shows that, because of the enormous space consumption caused by higher-speed car travel, land consumption rate increases are far out-pacing growth in community populations. For chartexample, from 1950 to 1990, the St. Louis population grew by 35 percent. Yet land consumption in St. Louis grew by 354 percent during that same period.

Given all of this, a centerpiece objective of the Boulder Transportation Master Plan (no more than 20 percent of road mileage is allowed to be congested) may not only be counterproductive in achieving many Boulder objectives, but may actually result in Boulder joining hands with the Sprawl Lobby.

The congestion reduction objective has a number of unintended, undesirable consequences. The objective tells Boulder that the highly desirable tactic of “road diets” (where travel lanes are removed to create a safer, more human-scaled street that can now install bike lanes, on-street parking, and wider sidewalks) are actually undesirable because they can increase congestion. The objective provides justification for looking upon a wider road, a bigger intersection, or a bigger parking lot as desirable, despite the well-documented fact that such gigantic facilities promote sprawl, car emissions, financial difficulties, higher taxes, and lower quality of life, among other detriments.

The objective also tells us that smaller, more affordable infill housing is undesirable—again because such housing can increase congestion.

The Shocking Revolution

The growing awareness of the problems associated with easing car travel (via such things as a congestion reduction objective) is leading to a shocking revolution across the nation. Florida, for example, now realizes that if new development is only allowed if “adequate” road capacity is available for the new development (which is based on “concurrency” rules in Florida’s Growth Management law), the state is powerfully promoting sprawl. Why? Because the available road capacity tends to only be found in sprawl locations. In-town locations, where new development tends to be much more desirable, is strongly discouraged by this Florida concurrency rule because in-town locations tend to have no available road capacity (due to existing, more dense development in town).

As an aside, “concurrency” is a rule that says new development is not allowed if it will lower service level standards adopted by the community. For example, standards might state that there must be at least 10 acres of parkland provided for every 1,000 residents. While concurrency is clearly a good idea for such things as parks and water supply and schools, it is counterproductive for roads.

The shocking revolution in Florida, then, is that the state is now allowing local governments to create “exception areas” for road congestion. If the community can show that it is providing adequate bicycle, pedestrian and transit facilities, the state will grant the local government the ability to create road exceptions so that the road congestion avoidance strategy brought by Florida’s road concurrency rule does not significantly encourage new sprawl and discourage in-town, infill development.

Similarly, California is now acknowledging the unintended, undesirable effects of past efforts to ensure that roads are “free-flowing” for car traffic. “Free flowing” car traffic tends to be measured with “level of service” (LOS) measures. Road LOS is a measure of traffic delay. An intersection (or road) where a car must wait for, say, three cycles of a traffic signal to be able to proceed through the intersection might be given an LOS rating of “F.” An intersection where a car can proceed through an intersection without such delay is given an LOS rating of “A.”

California now realizes that too often, building wider highways or stopping new development as a way to maintain free-flowing car traffic (LOS “A”) is substantially counterproductive. The state now realizes that maintaining or requiring easy, free-flowing car traffic increases greenhouse gas emissions (shocking, since the opposite was formerly believed), increases the number of car trips, and decreases the number of walking, bicycling and transit trips. Free-flowing road “LOS” measures are therefore now being phased out in California.

The “congestion reduction” objective in Boulder’s transportation plan is, in effect, a “happy cars” objective that equates easy car travel with quality of life and sustainability. One important reason why this “happy cars” objective is counterproductive is that cars and people have dramatically different needs and desires—needs and desires that are significantly and frequently in conflict. For example, designing shopping for happy people means the creation of smaller, human-scaled settings where buildings rather than parking lots are placed next to the streetside sidewalk. Where streets are only two or three lanes wide and designed for slow-speed car travel. Where street trees hug the street.

Designing shopping for happy cars, by strong contrast, requires huge car-scaled dimensions. Giant asphalt parking lots are placed between the now giant retail store and the street, which invites easy car parking (but loss of human scale, sense of place, and ease of walking). Streets become what Chuck Marohn calls “stroads”:  5- or 7-lane monster roads intended for dangerous, inhospitable high-speeds. They are roads where streets belong, but their big size and high speeds make them more like roads. Street trees are frequently incompatible with happy cars, as engineers fear cars might crash into them.

Again, this comparison shows that by promoting “happy cars,” Boulder’s congestion reduction objective is undermining its important quality of life and city-building objectives.

Indeed, Enrique Penalosa, the former mayor of Bogota, Columbia, once stated that “a city can be friendly to people or it can be friendly to cars, but it can’t be both.” Boulder’s congestion reduction objective is in conflict with this essential truth.

Fortunately, congestion regulates itself if we let it. Congestion will persuade some to drive at non-rush hour times, or take less congested routes, or travel by walking, bicycling, or transit. Congestion therefore does not inexorably lead to gridlock if we don’t widen a road or intersection, because some car trips (the “lower-value” trips) do not occur. Many of those discouraged trips are foregone because of the “time tax” imposed by the congestion.

But widening a road (or, in Boulder’s case, adding a second left-turn lane) short-circuits this self-regulation. A widened road or a double-left turn lane intersection induces new car trips because the road/intersection is now (briefly) less congested. The lower congestion encourages formerly discouraged car trips to now use the route during rush hour. Car trips that used different routes to avoid the congestion now converge back on the less congested route. And some get back in their cars after a period of walking, bicycling or using transit.

The process is very much like the infamous Soviet bread lines. The Soviets wanted to reduce the extremely long lines of people waiting for free bread. Their counterproductive “solution” was to make more free bread. But more free bread just induced more people to line up for bread. Likewise, the conventional American solution to traffic congestion is to make more free space for cars (widening the road or adding a second turn lane). The result is the same, as the bigger roads and intersections inevitably induce more car trips on those routes. The efficient and effective solution, as any first-year economics student will point out, is to NOT make more free bread or wider, free-to-use roads or second turn lanes. The solution is to price the bread and the car routes so that they are used more efficiently (and not wastefully by low-value bread consumers or car travelers). Or, to let a moderate level of congestion discourage low-value rush hour trips.

Given all of this, widening a road or adding a second left-turn lane to solve congestion is like loosening one’s belt to solve obesity. Similarly, despite conventional wisdom, car traffic does not behave like water flowing through a pipe (i.e., flowing easier if the pipe is expanded in size). Car traffic, instead, behaves like a gas. It expands to fill the available, increased volume provided.

Boulder’s Overriding Objectives

Boulder (and PLAN-Boulder County) has outlined key community objectives.

1. One is higher quality of life and more happiness. But counterproductively, happy cars lower quality of life due to clashing values and needs.

2. Another objective is for a more compact, walkable, vibrant city. Unfortunately, over-emphasizing cars means more sprawl.

3. An objective that is much talked about in the area is more affordability. By inducing more car dependence via easier car travel, the congestion reduction objective undermines the affordability objective by making Boulder less affordable (more on that later).

4. Given the growing concern for global warming, Boulder is placing more emphasis on reducing greenhouse gas emissions. Easing traffic congestion, however, induces new car traffic, which increases car emissions.

5. Boulder and PLAN-Boulder County seek more travel (and lifestyle) choices. But the congestion reduction objective in Boulder’s plan is again undercutting other objectives because it leads to bigger car infrastructure (bigger roads and intersections), thereby reducing travel and lifestyle choices.

As shown above, then, Boulder’s congestion reduction objective undermines each of these five essential community objectives.

Oops.

Conventional methods of reducing congestion include wider roads, bigger parking lots, one-way streets, and huge intersections. These tactics are a “win-lose” proposition. While they can reduce congestion (briefly), they also cause a loss of human scale and charm; a loss of social gathering; sprawling dispersal; more car dependence and less bicycling, walking, transit; higher taxes; economic woes (for government, shops and households); a decline in public health; and more air pollution.

By striking contrast, other less commonly used but much more beneficial transportation tactics are “win-win” propositions. Some of these tactics include road diets, designing streets for slower speeds, and designing for travel and lifestyle choices. They can result in:

  • More parking spaces
  • More civic pride (induced by human scale)
  • More social gathering
  • A more compact and vibrant community
  • Less car dependence and more bicycling, walking, and transit
  • Lower taxes
  • Economic health (for both government and households)
  • Improvement in public health
  • Less air pollution

If we can’t get rid of congestion, what CAN we do? We can create alternatives so that those who are unwilling to tolerate the congestion can find ways to avoid it. Congestion can be better avoided if we create more housing near jobs, shops, and culture. Doing this allows more people to have better, more feasible ways to travel without a car. We can also create more travel routes, so that the congested routes are not the only routes to our destinations. Some of us can be given more flexible work schedules to shift our work hours away from rush hour. And some of us can be given increased opportunities to telecommute (work from home).

How Can We Design Transportation to Achieve a Better Destiny?

An important way to start Boulder on a better destiny for the city is to revisit the “No more than 20 percent congested road miles” objective in the Boulder transportation master plan. Some possibilities: adopt a “level of service standard” not for cars, but for bicycle, walking and transit travel; “Level of service” standards for cars is becoming outdated because it is being increasingly seen as counterproductive, as described earlier. Other alternatives to the “congestion” objective is to have a target of controlling or reducing vehicle miles traveled (VMT) community-wide; or set a goal of minimizing trip generation by individual new developments in the city.

Another option is to keep the congestion objective, but create “exception” areas where the congestion rule does not apply. Those exception areas would be places where Boulder seeks to encourage new development.

Boulder needs to ensure that the community land development and transportation design tactics are appropriately calibrated within each “transect zone” of the community. (The “transect” principle identifies a transition from urban to rural, whereby the town center is more compact, formal, low-speed, and walkable; the suburbs are more dispersed, informal, higher-speed, and drivable; and the rural areas most remote from the town center are more intended for a farming and conservation lifestyle. Development regulations and transportation designs are calibrated so that the differing lifestyle and travel objectives of each zone are best achieved.) However, the difficulty with the transect principle in places like Boulder is that the demand for compact, walkable lifestyles and travel choices is much higher than the supply of such places in Boulder. There is, in other words, a large mismatch. By contrast, the supply of suburban, drivable areas is quite high. To correct this imbalance, Boulder should strive to create a larger supply of compact, walkable places similar to Pearl Street Mall, the Boulder town center, and even the CU campus. Opportunities now being discussed are the creation of new, compact villages and town centers at places such as street intersections outside of the Boulder town center.

As an aside, the community transect concept informs us that in the town center, “more is better.” That is, the lifestyle being sought in the community center is one where more shops, more offices, and more housing enhances the lifestyle, as this more proximate, mixed, compact layout of land uses provides the thriving, sociable, convenient, vibrant, 24-hour ambience that many seeking the walkable lifestyle want more of.

By contrast, in the more drivable suburbs, “more is less.” That is, the drivable lifestyle is enhanced in quality when there is less density, less development, more dispersal, and more isolation of houses from shops and offices. The ambience generally desired is more quiet and private.

While town center housing is increasingly expensive compared to the suburbs—particularly in cities such as Boulder—such in-town housing provides significant cost savings for transportation. Because such a housing location provides so many travel choices beyond car travel, many households find they can own two cars instead of three or one car instead of two. And each car that a household can “shed” due to the richness of travel choices provides more household income that can be directed to housing expenses such as a mortgage or rent. Today, the average car costs about $9,000 per year to own and operate. In places that are compact and walkable, that $9,000 (or $18,000) per year can be devoted to housing, thereby improving affordability.

In addition to providing for the full range of housing and travel choices, Boulder can better achieve its objectives through road diets, where travel lanes are removed and more space is provided for such things as bike lanes or sidewalks or transit. Road diets are increasingly used throughout the nation—particularly converting roads from four lanes to three. Up to about 25,000 vehicle trips per day on the road, a road that is “dieted” to, say, three lanes carries about as much traffic as a four-lane road. This is mostly due to the fact that the inside lanes of a four-laner frequently must act as Untitledturn lanes for cars waiting to make a left turn. Four-lane roads are less desirable than three-lane streets because they induce more car trips and reduce bicycle, walking and transit trips. Compared to three-lane streets, four-lane roads result in more speeding traffic. As a result, four-laners create a higher crash rate than three-lane streets. Finally, because the three-lane street is more human-scaled, pleasant, lower-speed, and thereby place-making, a three-lane street is better than a four-lane street for shops. The three-lane street becomes a place to drive TO, rather than drive THROUGH (as is the case with a four-lane street).

If Boulder seeks to be transformative with transportation—that is, if the city seeks to significantly shift car trips to walking, bicycling and transit trips (rather than the relatively modest shifts the city has achieved in the past)—it must recognize that it is NOT about providing more bike paths, sidewalks, or transit service. It is about taking away road and parking space from cars, and taking away subsidies for car travel.

Another transportation tactic Boulder should pursue to achieve a better destiny is to unbundle the price of parking from the price of housing. People who own less (or no) cars should have the choice of opting for more affordable housing—housing that does not include the very expensive cost of provided parking. Currently, little or no housing in Boulder provides the buyer or renter the option of having lower cost housing payments by choosing not to pay for parking. Particularly in a place like Boulder, where land values are so high, even housing intended to be relatively affordable is more costly than it needs to be because the land needed for parking adds a large cost to the housing price. Indeed, by requiring the home buyer or renter to pay more for parking, bundled parking price creates a financial incentive for owning and using more cars than would have otherwise been the case.

Boulder should also strive to provide parking more efficiently by pricing more parking. Too much parking in Boulder is both abundant and free. Less parking would be needed in the city (which would make the city more affordable, by the way) if it were efficiently priced.  Donald Shoup recommends, for example, that parking meters be priced to ensure that in general, 2 or 3 parking spaces will be vacant on each block.

Efficient parking methods that could be used more often in Boulder include allowing shops and offices and churches to share their parking. This opportunity is particularly available when different land uses (say churches and shops) don’t share the same hours of operation. Again, sharing more parking reduces the amount of parking needed in the city, which makes the city more compact, walkable, enjoyable and active.

Like shared parking, leased parking allows for a reduction in parking needed. If Boulder, for example, owns a parking garage, some of the spaces can be leased to nearby offices, shops, or housing so that those particular land uses do not need to create their own parking.

Finally, a relatively easy and quick way for Boulder to beneficially reform and make more efficient its parking is to revise its parking regulations so that “minimum parking” is converted to “MAXIMUM parking.” Minimum parking rules, required throughout Boulder, are the conventional and increasingly outmoded way to regulate parking. They tell the developer that at least “X” amount of parking spaces must be provided for every “Y” square feet of building. This rule almost always requires the developer to provide excessive, very expensive parking, in large part because it is based on “worst case scenario” parking “needs.” That is, sufficient parking must be provided so that there will be enough on the busiest single day of the year (often the weekend after Thanksgiving). Such a provision means that for the other 364 days of the year, a large number of parking spaces sit empty, a very costly proposition.

In contrast, maximum parking rules tell the developer that there is an upper limit to the number of spaces that can be provided. This works much better for the community and the business because the business is better able to choose how much parking it needs and can finance. Since financial institutions that provide financing for new developments typically require the developer to provide the conventional (read: excessive) amounts of parking as a condition for obtaining a development loan, the big danger for communities in nearly all cases is that TOO MUCH parking will be provided rather than too little. The result of setting “maximum” instead of “minimum” parking rules is that excessive, worst case scenario parking developments become much more rare.

The reform of parking is easy: simply convert the existing minimum parking specifications to maximum parking standards (“at least 3 spaces per 1,000 square feet” becomes “no more than 3 spaces per 1,000 square feet). An incremental approach to this conversion is to apply maximum parking rules in those places that are already rich in travel choices, such as the Boulder town center.

Again, what will Boulder’s destiny be? As the preceding discussion sought to demonstrate, much of that destiny will be shaped by transportation decisions.

Will destiny be shaped by striving for happy people and happy places for people? Or will it be shaped by opting for the conventional, downwardly-spiraling effort of seeking easy car travel (and thereby unpleasant places where only a car can be happy – such as huge highways or parking lots)?

Will Boulder, in other words, retain or otherwise promote place-less conventional shopping centers full of deadening parking, car-only travel, lack of human interaction, and isolation? Or will the city move away from car-happy objectives such as the congestion reduction policy, and instead move toward a people-friendly future rich in sociability, pride in community, travel choices, sustainability, place-making and human scale?

An example of these contrasting destinies is Pearl Street. West Pearl features the charm and human scale we built historically. West Pearl Street exemplifies a lovable, walkable, calm, safe and inviting ambience where car speeds are slower, the street is more narrow, and the shops—by being pulled up to the streetside sidewalk—help form a comfortable sense of enclosure that activates the street and feels comfortable to walk. The shops tend to be smaller—more neighborhood-scaled.

East Pearl Street near 28th Street is starkly different. There, the street is a “stroad,” because it is an overly wide road that should be a more narrow, lower-speed street. Shops are pulled back long distances from the street. The street here is fronted not by interesting shop fronts but enormous seas of asphalt parking. The layout is car-scaled. The setting is hostile, unpleasant, unsafe, stressful and uninviting. The shops tend to be “Big Box” retail, and serve a regional “consumershed.” There is “no there there.”

East Pearl Street was built more recently by professional planners and engineers who have advanced degrees that far exceed the professionalism and education of those who designed the more lovable West Pearl Street. Where has the charm gone? Why have our streets become less pleasant in more recent years (by better trained and better educated designers, I might add)? Is it perhaps related to our more expensive and sophisticated efforts to ease car traffic and reduce congestion?

There is an inverse relationship between congestion and such measures as vehicle miles traveled and gas consumption. At the community level—despite the conventional wisdom—as congestion increases, vehicle miles traveled, gas consumption, air emissions DECREASE. And as conventional efforts to reduce congestion intensify, quality of life and sustainability also decrease.

Again, is Boulder aligning itself with the Sprawl Lobby by maintaining an objective of easing traffic flow – by striving to reduce congestion?

On Controlling Size

David Mohney reminds us that the first task of the urban designer is to control size. This not only pertains to the essential need to keep streets, building setbacks, and community dispersal modest in size. It also pertains to the highly important need to insist on controlling the size of service and delivery trucks. Over-sized trucks in Boulder lead the city down a ruinous path, as street and intersection dimensions are typically driven by the “design vehicle.” When trucks are relatively large, excessive truck size becomes the “design vehicle” which ends up driving the dimensions of city streets. A healthy city should be designed for human scale and safety, not for the needs of huge trucks. Indeed, because motor vehicles consume so much space, a sign of a healthy, well-designed community is that drivers of vehicles should feel inconvenienced. If driving vehicles feels comfortable, it is a signal that we have over-designed streets and allocated such excessive spaces that we have lost human scale and safety.

A proposal for human-scaled streets: in Boulder’s town center, no street should be larger than three lanes in size. Outside the town center, no street should be larger than five lanes in size. Anything more exceeds the human scaling needed for a pleasant, safe, sustainable community.

It is time to return to the timeless tradition of designing to make people happy, not cars. Boulder needs to start by revisiting its congestion reduction objective, putting a number of its roads on a “road diet,” and taking steps to make the provision of parking more efficient and conducive to a healthy city.

________________________________________

 More about the author

 Mr. Nozzi was a senior planner for Gainesville FL for 20 years, and wrote that city’s long-range transportation plan. He also administered Boulder’s growth rate control law in the mid-90s. He is currently a member of the Boulder Transportation Advisory Board.

 Studies Demonstrating Induced Traffic and Car Emission Increases

Below is a sampling of references to studies describing how new car trips are induced by easier car travel, and how car emissions increase as a result.

http://www.sierraclub.org/sprawl/articles/hwyemis.asp

http://www.vtpi.org/gentraf.pdf

http://en.wikipedia.org/wiki/Induced_demand

https://walkablestreets.wordpress.com/1993/04/18/does-free-flowing-car-traffic-reduce-fuel-consumption-and-air-pollution/

TØI (2009), Does Road Improvement Decrease Greenhouse Gas Emissions?, Institute of Transport Economics (TØI), Norwegian Centre for Transport Research (www.toi.no); summary at www.toi.no/getfile.php/Publikasjoner/T%D8I%20rapporter/2009/1027-2009/Sum-1027-2009.pdf

Robert Noland and Mohammed A. Quddus (2006), “Flow Improvements and Vehicle Emissions:

Effects of Trip Generation and Emission Control Technology,” Transportation Research D, Vol. 11 (www.elsevier.com/locate/trd), pp. 1-14; also see

www.cts.cv.ic.ac.uk/documents/publications/iccts00249.pdf

Clark Williams-Derry (2007), Increases In Greenhouse-Gas Emissions From Highway-Widening Projects, Sightline Institute (www.sightline.org); at

www.sightline.org/research/energy/res_pubs/analysis-ghg-roads

TRB (1995), Expanding Metropolitan Highways: Implications for Air Quality and Energy Use,

Committee for Study of Impacts of Highway Capacity Improvements on Air Quality and Energy

Consumption, Transportation Research Board, Special Report #345 (www.trb.org)

D. Shefer & P. Rietvald (1997), “Congestion and Safety on Highways: Towards an Analytical Model,” Urban Studies, Vol. 34, No. 4, pp. 679-692.

Alison Cassady, Tony Dutzik and Emily Figdor (2004). More Highways, More Pollution: Road Building and Air Pollution in America’s Cities, U.S. PIRG Education Fund (www.uspirg.org).

http://www.opr.ca.gov/docs/PreliminaryEvaluationTransportationMetrics.pdf

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Filed under Bicycling, New Urbanism: Timeless, Traditional, Walkable Design, Parking, Sprawl and Suburbia, Traffic Congestion, Walkable Streets Speaking and Consulting

Many Cities Changing One-Way Streets Back

By Melanie Eversley, USA TODAY

12/20/06

More traffic will be coming to downtown Danville, Ill. — and that’s how Danville wants it. The city of 33,000 is converting some of its longtime one-way streets back to two-way thoroughfares. City officials hope the change will make it easier for customers to reach downtown stores and shop in them.

“The driving force behind it is economic development,” says city engineer David Schnelle, who expects to reprogram signals, change pavement markings and change signs by November 2007.

He says motorists tend to drive faster on one-way streets and go past their destinations, then lose time and patience backtracking.

Danville is one of hundreds of cities — from Berkeley, Calif., to Charleston, S.C. — switching one-way streets to two-way to improve commerce downtown, according to the American Planning Association in Chicago. The trend got rolling in the early 1990s and has expanded this year to bigger cities such as Miami, Dallas and Minneapolis. It’s part of the reinvention of former industrial cities, which are converting empty factories into loft housing and trying to convince suburbanites that downtowns are livable.

“There’s a lot of emphasis now on taming the automobile and emphasizing walking and biking. It’s all part of creating a place that people want to be,” says Marya Morris of the American Planning Association. “The bigger pieces are the major downtown housing booms and having things for people to do after 5.”

The boom in one-way streets began with the Cold War in the 1950s, when cities planned quick routes out of town for evacuation in case of nuclear attack, says John Norquist, one of the first vocal advocates of two-way-street conversion. Norquist was mayor of Milwaukee from 1988 to 2003 and now runs the Congress for the New Urbanism, which promotes the revitalization of cities.

The growth of the suburbs contributed, too, as cities smoothed the route home from work, says Neal Hawkins, associate director for traffic operations at the Iowa State University Center for Transportation Research and Education. Now, though, there are more jobs in the suburbs, more entertainment downtown, and drivers go in all directions.

They drive less efficiently on two-way streets, according to the Thoreau Institute, an environmental advocacy group in Oregon. The slower stop-and-go traffic means cars pollute more, the institute says.

In Danville, 170 miles south of Chicago, two-way streets are meant to speed an economic revival after 15 years of plant closings left downtown streets quiet. The city set up a small-business loan program to attract stores and restaurants.

Now Danville wants to make it easier for customers to find them, especially the shops on Vermilion Street.

Marie Pribble, co-owner of the Java Hut coffee shop and cafe, looks forward to the change. “The slower people go, the more likely they are to pay attention to your business or your storefront, and the more likely they are to stop in,” she says.

Norquist was one of the first mayors to promote more two-way streets. He led a campaign to convert several downtown Milwaukee streets back to two-way. He says the increased traffic means that neighborhoods flourish: “I think people started to realize that the city was more important than the road that runs through it.”

 

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Recipe for Creating a Bicycle-Friendly City

By Dom Nozzi, AICP

What are the ingredients for creating a bicycle-friendly community? A community that feels safe, convenient and pleasant for all ages and abilities to ride a bicycle. It is important to understand, to begin with, that there are no easy, painless, overnight solutions. Over the past several decades, we have unconsciously done everything we could possibly do to make bicycling an exceptionally dangerous, unacceptable way to travel. It will therefore take quite a while for our cities and towns to see bicyclists crowding our streets. And change will need to be incremental and from a great many sources. There are no silver bullets.

Here are my top 5 recommendations for how to make a more bicycle-friendly community.

1. Parking Cash-Out. Local employers (particularly local government agencies and large private employers) must establish a parking cash-out program. By ending this enormous subsidy for driving a car to work, cash-out is the most effective tool we know of to recruit new bicyclists. An increased number of bicycle commuters dramatically increases bicyclist safety and comfort while riding, and promotes political action to improve bicycling conditions.

2. Centralization and Residential Density. Important facilities and events, such as the county farmers market, the conference center, the major movie theatre complex, the major fitness center, the main post office, major government facilities, and annual festivals must only be allowed in the central area of the city (subsidiary or duplicate facilities and events can be allowed in the periphery). Those facilities and events that are currently located in peripheral locations must be incrementally moved to central locations. Locating these facilities and events at peripheral locations substantially reduces their accessibility by a large percentage of commuter bicyclists. Such an effort is not only crucial to bicycling, but is also essential in creating a sense of community. Similarly, a city must establish higher density residential development within the central areas of the city. Doing so dramatically increases bicycling because such housing increases the convenience, safety and practicality of bicycling. Destinations such as school, retail, recreation, government facilities, jobs and culture become more proximate (more w/in bicycling range).

3. Traffic Calming and Road Diets. High-speed, inattentive car travel is one of the most significant reasons bicyclists feel unsafe and uncomfortable while bicycling — and why so many are discouraged from bicycling at all. Each time a street is traffic-calmed, or has travel lanes removed (road dieting), bicycling is dramatically improved and there is a significant increase in bicycling. A large percentage of streets carry car traffic that features uncomfortably and unsafely high speeds, and a number of streets can greatly benefit from travel lane removal (for example, 5- or 4-lanes to 3). Many of these diet opportunities provide a way to install an in-street bicycle lane on streets that do not have space today, and in-street bicycle lanes are, by far, preferable to off-street paths for commuter bicycle travel. Because 4-, 5-, and 6-lane streets are a primary cause of high speed car traffic and inattentive, reckless driving, it is important for a community to avoid building them, and to “diet” those that are already at that size. High-speed, inattentive driving significantly discourages bicycling in most every community.

4. Off-Street Path System. The off-street bicycle/pedestrian path system in nearly every community is either non-existent, or contains a number of path opportunities that have languished, unbuilt, for decades. The gaps in this “greenway” system must be eliminated. While completing the system will not result in a significant increase in bicycle commuting, it would dramatically increase recreational bicycling. A completed greenway system also plays the crucial role of recruiting novice bicyclists and non-bicyclists into becoming regular, confident bicyclists, because off-street paths provide a “training ground” that allows large numbers of untrained bicyclists to learn the skills and joys of bicycling in a safe, non-threatening, sociable environment.

5. In-Street Bicycle Lanes. Despite what is often believed, in-street bicycle lanes are much more desirable to a commuter bicyclist than are off-street paths or sidewalks. Paths can only feasibly link a tiny number of destinations that a bicyclist seeks to travel to, and even for the small number of destinations that can be reached by a path, using the street is nearly always faster and more direct than using an off-street path. And just like motorists, a primary desire by bicyclists is to find the fastest route to a destination when commuting. In addition, contrary to popular belief, studies have shown for several decades that in urbanized areas where there are numerous crossing driveways and streets, in-street bicycle lanes are significantly safer than sidewalks. Because paths usually create the same safety hazards as sidewalks (by having numerous driveway and street intersections), they are generally discouraged as a design treatment within urbanized areas. Given all of this, a bicycle-friendly city must ensure that as many major streets as possible contain in-street bicycle lanes. It is important to keep in mind that one size does not fit all. In general, in-street bicycle lanes are NOT appropriate on low-speed downtown streets or neighborhood streets. Their application tends to be most appropriate on higher-speed suburban arterial streets.

References for #5 above:

Florida Dept of Transportation (1998). Florida Bicycle Facilities Planning and Design Manual. Tallahassee FL.

Florida Dept of Transportation (2002). Plans Preparation Manual. Tallahassee FL.

Wachtel, A. and Lewiston, D. (1994). Risk Factors for Bicycle-Motor Vehicle Collisions at Intersections. ITE Journal. September.

Forester, J. (1984). Effective Cycling. MIT Press.

Forester, J. (1983). Bicycle Transportation. MIT Press.

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Filed under Bicycling

Local Government Opposition to Smart Growth

By Dom Nozzi, AICP

Smart growth (according to Wikipedia) is a concept and term used by those who seek to identify a set of policies governing transportation and land use planning policy for urban areas that benefits communities and preserves the natural environment. Smart growth advocates land use patterns that are compact, transit-oriented, walkable, bicycle-friendly, and include mixed-use development with a range of housing choices. This philosophy keeps density concentrated in the center of a town or city, combating suburban sprawl.

Proponents of smart growth advocate comprehensive planning to guide, design, develop, revitalize and build communities that: have a unique sense of community and place; preserve and enhance natural and cultural resources; equitably distribute the costs and benefits of development; expand the range of transportation, employment and housing choices; value long-range, regional considerations of sustainability over a short-term focus; and promote public health and healthy communities.

Are Local Governments the Champions of Smart Growth?

The conventional wisdom holds that developers in the private sector, left to their own devices, will resist or be otherwise unaware of the smart growth objectives of a community. That local government and its land development regulations are necessary to ensure that developers engage in developments that deliver smart growth.

It is expected that democratically-elected local governments would champion smart growth, as opinion polls consistently show large majorities who are opposed to suburban sprawl, and one would expect that local government representatives would “carry out the will of the people.”

However, while majorities pay lip service to opposing sprawl, surveys also show that nearly all of the tactics necessary to effectively slow sprawl are also opposed. More and more, “not in my backyard” (NIMBYs) neighborhood activists attend public meetings to fight against smart growth tactics.

How can this be?

Simply put, a number of factors in our world have come together to create an environment in which we have become our own worst enemies – unintentionally working against our own interests.

For example, the emergence of the car, as a form of travel, has been coupled over the past century with exceptionally low-cost oil necessary to power this form of travel. This enabled a population flight from the pollution and crime of the city into the suburbs. Home mortgages and enormous road widening campaigns further promoted an escape from the city. Free and abundant auto parking was not only provided but required for new developments as a way to accommodate a population that was now traveling by car.

Unfortunately, the car carries with it some tragic consequences.

First, creating a world that provides for car travel inevitably results in a growing inability to travel by foot, by bicycle or by transit. Economists call this the “barrier effect.”

Because the barrier effect continuously recruits new motorists who were formerly walking, bicycling or using transit, a growing percentage of the population travels by car.

The distorted market (subsidized gas, roads and parking) combines with a growing number of motorists (many of which have been created by the barrier effect) to create an enormous and ever-growing number of vocal, aggressive advocates for community design which promotes car travel.

This state of affairs could perhaps be tolerable except for one simple fact: The interests, needs and values of people are nearly the opposite of the needs of cars. Cars work best when roads are wide and high-speed. When parking lots are endless in size and easy to find. When building setbacks are large. When there are only a tiny number of other cars on the road. People, on the other hand, largely seek the reverse. The human habitat is most desirable when roads are narrow in size and slow in speed. When parking lots are small and hidden away. When building setbacks are modest. And as a gregarious species by nature, humans enjoy the sociability of congregations of people in our travels.

The tragic dilemma, then, is that as people are increasingly finding themselves compelled to travel by car, they increasingly find themselves obligated, unintentionally, to request community design that works against their own quality of life.

In the end, the decline in civic pride and sociability that comes from car travel advocacy leads to a “cocooning” tendency in which people increasingly turn inward. People turn away from the public realm. Houses and commercial buildings pull themselves away from hostile, raceway roads and turn their backs to it. The public realm declines in quality as it is increasingly neglected and held at arms length.

Instead, quality of life is to be achieved by creating a luxurious private realm. The insides of our SUVs, the insides of our commercial buildings, and the insides of our suburban homes become palatial. Outside, our streets, sidewalks and squares become ignored, unkempt “no man’s lands” where only a tiny number (of those without the money to own a car) are found.

What follows is a list of common regulatory strategies that most communities use to block smart growth efforts proposed by developers and promote car travel.

 

1. FAR (floor area ratio) limits in areas intended to be walkable. The higher the percentage of floor area for a given parcel of land, the more compact and walkable the design can be. Therefore, setting FAR limits tends to inhibit walkability.

2. Maximum residential densities in areas intended to be walkable. Higher densities promote walking, discourage excessive car travel, reduce energy consumption, improve the health of small- and neighborhood-based shops, increase citizen surveillance, promote independence of travel for seniors and children, promote affordable housing. Therefore, setting density limits in areas intended to be walkable tends to inhibit walkability.

3. Environmental regulations that are not relaxed in-town. Strict in-town environmental regulations (where the environment tends to be relatively degraded anyway) add another layer of discouraging costs for in-town development and redevelopment. Such infill is already disadvantaged by enormous public subsidies promoting sprawl (mostly road and parking). In addition, the habitat for wildlife tends to be incompatible with the habitat for humans (spaces tend to be too large to walk, nuisances such as insects, unkempt vegetation and water tend to be extreme, etc.).

4. Mixed use limits (and overall employment of use-based instead of form-based coding, the latter of which increases predictability and therefore infill investment). Mixed-use promotes transportation choice, affordable housing, sidewalk vibrancy, citizen surveillance, reduction in excessive car travel, improved business climate (less need for costly rezonings). Most communities prohibit residences in commercial areas and commercial in residential areas.

5. Minimum parking requirements. Such requirements create an excessive amount of free, unwalkable, unpleasant, unsafe seas of asphalt. Such car storage areas deaden the financial and social vibrancy of an area. They encourage excessive car use and discourages transportation choice. They enable long-distance travel by car. They increase the cost of goods and services (because parking is not free for businesses which must provide it). They make housing less affordable.

6. Minimum lot size. Such a regulation makes housing less affordable. It creates a less compact, less walkable design. It therefore tends to reduce transportation choice.

7. Minimum lot width. Like minimum lot size, such a regulation makes housing less affordable. It creates a less compact, less walkable design. It therefore tends to reduce transportation choice. It also tends to reduce sidewalk vibrancy.

8. Large and required building setbacks. Such a regulation makes development less walkable, thereby reducing transportation choice. It reduces housing affordability. The public realm is degraded as a human-scaled sense of enclosure (through the creation of “outdoor rooms”) is extinguished.

9. Minimum public school playing field size. This requirement chases a large number of neighborhood-based, walkable public schools from in-town, walkable neighborhoods, since such neighborhoods tend not to have the space to accommodate such large school sites. Such a requirement also discourages the retrofitting of walkable, neighborhood-based schools into existing neighborhoods.

10. Large stormwater basin requirements (and allowing basins at street). This requirement frequently creates unwalkable site development design. The public realm is degraded as a human-scaled sense of enclosure is less possible.

11. Allowing parking lots in front of buildings and at intersections. This requirement frequently creates unwalkable site development design. The public realm is degraded as a human-scaled sense of enclosure is less possible. (This issue pertains to a lack of a regulation.)

12. Prohibition on awnings, canopies, colonnades, cafes in ROW. This makes the character-rich, romantic, walkable, weather-sheltering traditional design of storefronts illegal.

13. Large vision triangle and huge turning radius. Tends to increase the turning speed of motor vehicles and reduces the attentiveness of drivers. Tends to increase crossing distance exposure of pedestrians across street intersections. Tends to reduce the likelihood of a human-scaled sense of enclosure.

14. ADUs often not allowed. Accessory Dwelling Units (often called “granny flats”) are an easy way to create affordable housing and higher neighborhood densities, as well as improving household and neighborhood security.

15. Property tax based on building value rather than based only on land value. This tax system, used in nearly all American communities, financially penalizes development, redevelopment, infill and intensification of in-town properties, which promotes sprawl, reduces in-town vibrancy and retail health, reduces local government tax revenue, and strongly incentivizes the speculative holding of property in low-value uses such as surface parking.

16. Limiting the number of “families” (particularly in single-family residential zoning). This regulation is designed to indirectly control problems associated with too many cars (spillover parking, etc.). By limiting the number of families, we inhibit smart density increases and make affordable housing less likely.

17. Applying “One Size Fits All” Building Codes to Downtown. Nearly all communities have a building code that applies citywide. Often, as a result, property owners find that it is not cost-feasible to rehabilitate older, dilapidated buildings downtown because it is too costly to meet code requirements that would require, for example, hallways or doors to be widened for fire safety. Therefore, to incentivize the re-use of existing buildings, the State of New Jersey has adopted a “Rehabilitation Code.” The code resulted in a substantial increase in the amount of rehabilitation work in New Jersey urban areas during the first year the code was in place The code relaxes certain requirements without compromising safety. Overall, the argument could be made that because of the successful rehabilitation of New Jersey urban buildings, public safety has improved. (Healthier downtowns means less suburban motor vehicle travel, and the rehabbed buildings are often or always safer than in their previous state-even if they are not built to the statewide code for new buildings.)

18. Use-Based vs. Form-Based Codes. Most land development codes are focused on separating uses, ensuring that “sufficient” car parking is provided, and specifying what is not allowed. Very few, if any, of the regulations indicate what should be built. In addition, the quality of the public realm tends to be ignored (unless it is to provide a nice view for the passing motorist).

19. Wide travel lanes for roads. Tends to increase the speed of motor vehicles and reduces the attentiveness of drivers. Tends to increase crossing distance exposure of pedestrians across street intersections.

20. Resistance to “spot” zoning. Nearly all community planners and elected officials have a policy that dates back to the beginning of zoning regulations from the early part of the 20th century. Known as “spot” zoning, this strongly discouraged change in the use of land constitutes, usually, a proposal to change the zoning designation from residential use to commercial use on a piece of property that is surrounded by other properties zoned for residential. In the anachronistic interest of “segregating” dissimilar uses of land from each other, the underlying premise is that a rezoning is not appropriate when the proposed new zoning is unlike any zoning for adjacent property. Again, the idea harkens back a century ago when it was deemed important to separate noxious industrial activities from residential properties. Today, most of the opposition to “spot” zoning is based on a desire to minimize the nuisance of excessive car trips drawn by an isolated office or shop to surrounding residences – an important concern in an auto-dependent society. Ironically, resistance to “spot” zoning (often specifically prohibited in the community long-range plan) leads to a growth in per capita car travel, since such efforts squelch changes that would introduce neighborhood-based shops and offices that could be walked or bicycled to.

21. Road concurrency (and exceptions without meaningful design requirements). This rule strongly promotes suburban sprawl and suboptimizes the needs of cars over the needs of people and community. Most communities require that new development in urban areas not “degrade” free-flowing traffic conditions on nearby roads or otherwise create congested conditions. Because cars consume so much space, striving for free-flow results in the requirement that either enormous, unsafe and unwalkable roads be built, that density or intensity be kept as low as possible, or both. (Only a tiny number of people are necessary to congest a road, given the large size of cars. Striving for “tiny number” densities deadens an area and makes lively urbanism impossible.)

For nearly every planner, every elected official, and every citizen, when a new development is proposed, the overwhelming question (and often the only important one) is this: “Can the roads serving this new development handle the car trips that will be generated by the new development.” Regularly, the answer is “no.” Two “solutions” are generally suggested, both of which are deadly for city-building: (1) require the roads to be widened, at great expense to the developer, the local government, or both; or if this is not feasible, (2) deny the development permission to build. The first “solution” takes precious dollars away from much-needed community services and facilities. It also degrades the community quality of life because wider roads inevitably harms the human habitat. Cars become faster, louder, more dangerous and more necessary. The second “solution” takes away from the health of the city, as healthy cities require agglomeration economies. That is, a city is stronger and more fit as it adds more people and activities within a compact, diverse space. And denying projects on the basis of “insufficient” road capacity works at cross-purposes with the essential need of a city to strive for agglomeration. Life-giving energy and vitality are denied when a development is stopped due to insufficient road capacity. Conversely, over-sized roads diverts energy and vitality to outlying areas. In effect, then, contemporary local government planners are single-mindedly and ironically obsessed with a quest to strangle the life-blood out of a community.

Some communities in Florida grant exceptions to the statewide requirement that new development maintain free-flow conditions, but such communities generally do not require meaningful urbanism in exchange for the exception.

Each of these 20 items share at least one characteristic in common: they all profoundly and systematically degrade the public realm – the streets, the sidewalks, the public square, and other spaces where citizens have an opportunity to interact, and where the character and vibrancy of a community is perceived.

An overriding desire in an auto-dependent society is that new development should minimize the number of cars that would congest our roads and take up our parking spaces. That largely means that new development must either be stopped, or its density minimized (to reduce the number of cars that will hog our roads and parking lots). And unlike in the past, when this opposition came mostly from environmentalists, this form of anti-city advocacy now comes from all groups: Not just “Greens,” but also Republicans, Democrats, business owners, liberals, conservatives, the Chamber of Commerce, and even libertarians.

Increasingly, it is the private developer who most often leads the way in proposing smart growth developments, and must frequently face a barrage of time-consuming, costly and often fatal obstacles, such as those above. Rather than “evil” developers, all too often the most serious barrier to smart growth are obstacles, such as those listed above, put in place by local governments still trapped in the auto age.

 

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Filed under New Urbanism: Timeless, Traditional, Walkable Design, Sprawl and Suburbia

In Praise of Traffic Calming

By Dom Nozzi, AICP

For 50 years, transportation planners have treated streets as little more than conduits for motor vehicles, and see little need for roads other than to maximize motorist driving speeds. Sadly, in all except our remote subdivisions, the quality of life in cities designed for cars has become miserable. No wonder that so many flee the city for the relative safety, peacefulness, and pastoral nature of outlying areas.

According to Cynthia Hoyle, the U.S. has been so successful in providing for fast, unobstructed travel by car that it has seriously undermined the use of transit, walking, and bicycling.

Streets designed primarily with driving speed in mind deter people from walking and bicycling. They’re difficult and unattractive places to walk or bicycle to begin with, and the heavier, faster traffic they generate makes them downright hostile. Pedestrian street crossings are challenging and infrequent, sidewalks are anything but continuous, and anyone who ventures out on a bicycle is soon reminded by an impatient honking motorist that she’s in the way and doesn’t belong there. “Danger” and “road conditions” or “lack of facilities” are reasons more frequently given in surveys for not bicycling.

How big is the problem for Floridians? One example is the fact that 37 percent of Floridians cannot legally drive-not to mention those who cannot afford to own a car.

The proposed “design speed” for a road affects its dimensions more than anything else. It is the highest speed at which a motorist can drive safely. Not surprisingly, the bible of traffic engineers—”The Green Book”—calls for the design speed, except on local streets, to be as high as practicable.

A wide pavement exerts a strong influence over a motorist. First, it puts someone in a car at a greater distance from objects on either side. Looking at objects that are farther away creates a feeling that a vehicle is moving more slowly and prompts a motorist to compensate by speeding up. Second, by making the motorist survey a broad field in front of his vehicle, a wide pavement provides an assurance that he is in command of that field, which in turn induces him to increase his speed. In addition, when a wide pavement means more lanes, it leaves fewer vehicles in each lane and increases the distance between each vehicle, providing yet another inducement to go faster. Thus an urban arterial with three 11- or 12-foot travel lanes, or a broad two-lane residential street, can have a virtually irresistible effect. Even motorists who are not inclined to drive fast creep up to highway speeds. Others seize the opportunity to floor it.

Cutting down trees, removing other vegetation, taking property by eminent domain, and lowering hills create what traffic engineers assume is the necessary “stopping sight distance.” And the design speed of a road is the primary factor determining the stopping sight distance.

When a traffic engineer states the newly designed road will “improve safety,” beware. While it usually means fewer fender benders, it generally leads to more serious accidents and more accidents involving pedestrians. Making a street “safer” usually tends to increase motor vehicle speeds, which makes the streets less safe for pedestrians or bicyclists. Sixteen percent of all people killed in motor vehicle accidents are pedestrians and bicyclists, which is way out of proportion to the number of pedestrians and bicyclists on the streets. Thirty-nine percent of all children killed in motor vehicle accidents are killed while walking or riding a bicycle. When we hear traffic engineers tell us that the road “improvement” will improve safety, we need to ask them to precisely define what the safety problem is.

Alcohol, vehicle speed, weather, and animals are more important factors in accidents than road design.

Motorists driving at 25 mph or faster have difficulty perceiving that a pedestrian is ready to cross a street, deciding to slow down, and actually doing so. The normal driver usually decides to speed up, assuming that another car will stop.

Many homeowners have essentially written off their front yards as a place to be, largely because of the speed and volume of traffic. It is time that we start designing our communities for people instead of cars. And one of the emerging, exciting ways to do that is through use of “traffic calming.”

Traffic calming involves making design changes to a street or parking lot to slow down and “discipline” autos, and make streets mixed-use rather than single (auto)-use. Strategies include traffic circles (photo above), roundabouts (photo below), on-street parking, narrow travel lanes, reduction in travel lanes, woonerfs, traffic diverters sidewalk bulb-outs, speed humps, smaller turning radii at intersections (15 feet), and elevated/textured/brick crosswalks that serve as a speed hump.

Portland, Oregon has a “skinny streets” program for new residential areas. It allows residential streets to be 20 feet wide with parking on one side, or 26 feet with parking on both sides. The city notes that such streets maintain neighborhood character, reduce construction costs, save vegetation, reduce stormwater runoff, improve traffic safety, and make it possible to use scarce land for purposes other than motor vehicle use. The Portland Fire Department finds that skinny streets provide adequate access for emergency vehicles. It has been noted that it would be more economical to purchase fire trucks that fit local streets than to build all streets to meet the needs of the largest size trucks. Berkeley studies show that traffic control devices had little or no effect on police emergency response time, and Palo Alto found that bicycle boulevard barriers had not impaired police and fire emergency response.

Motorists are more likely to collide with pedestrians at higher speeds. At 60 miles per hour, the field of vision of the motorist is two-thirds less than at 30 miles per hour. In addition, the probability of a pedestrian being killed is only 3.5 percent when a vehicle is traveling at 15 miles per hour, but jumps to 37 percent at 31 miles per hour and 83 percent at 44 miles per hour.

Roadway geometry in safety-sensitive areas, such as schools, should keep auto speeds within 15 to 20 miles per hour. Planting vegetation close to the street will reduce the “optical width” of a street, which makes it seem narrower than it is and help to slow down motorists.

A German study found that traffic calming reduces vehicle idling time by 15 percent, gear changing by 12 percent, brake use by 14 percent, and gasoline use by 12 percent. This is in part because the greater is speed of vehicles in built-up areas, the higher is the incidence of acceleration, deceleration, and braking. Similarly, a study in Portland, Oregon found that a pedestrian-friendly environment can reduce vehicle miles traveled by 10 percent. Other studies show up to a 114-percent increase in non-motorized travel on traffic-calmed streets.

Another German study found that calmed streets experienced a 60 percent reduction in injuries, a 43 to 53 percent reduction in fatalities, and a 10 to 50 percent reduction in air pollution (Nitrogen oxide emissions, for example, begin to increase with speeds at about 15-20 mph, and then increase sharply with speed at about 48 mph.) These substantial benefits, in addition, were achieved by increasing motorist trip time by an average of only 33 seconds. Motorists who found the 18 mile-per-hour speed limit acceptable grew from 27 percent before the streets were calmed to 67 percent after the program began. Receptive residents along the streets grew from 30 percent before to 75 percent after.

Portland finds that traffic circles are most effective when constructed in a series. They are sometimes also located in the middle of the block. Circles reduce motor vehicle speeds and result in a big reduction in the number of accidents. Circles reduce crashes by 50 to 90 percent when compared to two-way and four-way stop signs and traffic signals by reducing the number of conflict points. Seattle likes circles so much that they build about 30 circles each year.

The Institute of Traffic Engineers (ITE) have stated that speed humps are effective in reducing vehicle speeds without increasing accident rates (some studies have found a reduction in accident rate). Humps cause motorists to experience little or no discomfort at speeds up to 25 mph, and need to be spaced close enough to each other so that motorists do not speed between them. The ITE has found that despite concerns about liability, vehicle damage and emergency vehicle impacts, these problems have not occurred or have been found to be insignificant when considering the positive impacts of humps.

And despite the conventional wisdom, stop signs do not affect overall traffic speeds or control speeding. Posting appropriate speed limits and enforcing them is not sufficient to achieve needed reductions in motorist speeds. Modest physical reconfiguration of streets are the only reliable and cost-effective way to slow and control traffic.

Calming also helps reduce neighborhood noise pollution. From a distance of 48 feet, a car traveling at 56 miles per hour makes ten times more noise than a car traveling at 31 miles per hour. Reducing average speed from 25 miles per hour to 12 miles per hour reduces noise levels by 14 decibels (ten times quieter). At higher speeds, every 12 to 15 miles per hour in speed increases results in a 4 to 5 decibel noise increase.

The City of Oakland recently budgeted $1 million to install traffic calming measures throughout the city in response to citizen petitions for safer streets. The City has already installed speed humps and is pursuing road narrowing and barriers to through traffic. A similar strategy in Menlo Park has reduced through traffic by 66 percent, has reduced top speeds by 40 percent, and has reduced average speed by 20 percent.

It is important to learn from our past in designing street intersections. For example, in the past, we designed corners with a small “radius.” A corner with a radius of 15 feet or less is usually appropriate to require turning vehicles to slow down, and also shortens the distance that a pedestrian must walk to get across the street.

A maximum driving speed of 19-25 mph is necessary to ensure safety, create an environment people find conducive to walking and shopping, and minimize noise. Fred Kent, a nationally known urban designer, says that in all the surveys he has done around shopping districts, the biggest problems are not security issues. They are traffic issues-the speed of vehicles, the noise of vehicles, the congestion. You realize that if you create less vehicle flow and slower vehicles, you create more of a sense of community and you increase the perception of safety and security.

Here are some of the benefits that a German city found by using traffic calming:

50 percent increase in bicycle use.

57 percent reduction in fatal accidents.

45 percent reduction in severe accidents.

40 percent reduction in slight injuries.

43 percent reduction in pedestrian accidents.

16 percent reduction in cyclist accidents.

16 percent reduction in traffic accident costs.

66 percent reduction in child accidents.

The Federal Highway Administration (FHA) has stated that traffic calming appears to be one of the more cost-effective ways to promote pedestrian and bicycle use in urban and suburban areas, where walking and bicycling are often hazardous and uncomfortable. By improving the quality of urban neighborhoods, traffic controls can help reverse the flight of the middle class away from the city. And as for children, Stina Sandels, a world authority on children and road accidents says that the best road safety education cannot adapt a child to modern traffic, so traffic must be adapted to the child.

The FHA notes that the importance of reducing traffic speed cannot be overemphasized. While the overall goals of slowing traffic may include environmental improvements, better conditions for bicyclists and pedestrians, accident reductions, and more space for children to play-the reduction in vehicle speeds is crucial to each.

The primary question has become whether or not the city, which was formerly built on the human scale, and in which the street existed primarily as a means of contact, is to be replaced by a sprawled megalopolis where the dimensions of the street and city are on a scale required for its primary use by motorized transportation, and whether we will let our quality of life and sustainability remain terrible-all in the name of making cars happy.

References:

Traffic Calming by Cynthia Hoyle

Traffic Calming by CART (David Engwicht)

Sustainable Community Transportation by Todd Litman

Taming the Automobile by Richard Untermann

Take Back Your Streets by the Conservation Law Foundation

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Filed under New Urbanism: Timeless, Traditional, Walkable Design

Context-Sensitive Street Design Literature

By Dom Nozzi, AICP

Too often, traffic engineering guidelines for a community takes a “one size fits all” approach. Such an approach nearly always adopts suburban, car-happy design as the default approach. Unfortunately, this severe restriction on freedom of travel and lifestyle choice means, to paraphrase Henry Ford, that you can choose any form of travel and lifestyle as long as it is suburban and car-dependent.

Since there will always be a meaningful number of citizens in our communities who seek not the suburban choice but the walkable, urban lifestyle (or neighborhoods that are safe for children, seniors and pets), it is essential that the traffic design manual contain tools sufficient to provide for the street design needed to create walkable, human-scaled places.

In recent years, the emerging term used to refer to this customize-able approach is the “context-sensitive” street design. Such design recognizes that once a high-speed suburban or highway design enters a community, a neighborhood, or a special, walkable district, it needs to transition into a more human-scaled design that obligates cars to drive in a slower, safer, more courteous and aware manner. The following are recommended citations for context-sensitive design for streets.

1. “Traffic Engineering for Neo-Traditional Neighborhood Design,” Feb. 1994. An Informational Report of the Institute of Transportation Engineers.

2. “Street Connectivity in Practice”, Planners Advisory Service Report #515 from the American Planning Association.

3. “Pedestrian Facilities User Guide” by FHA of the USDOT, March 2002.

4. “Street Standards” by Southworth & Ben-Joseph. APA Journal Winter 1995.

5. “The Design of Traditional Neighborhood Streets” by Rick Chellman, 9/98, from the Seaside Institute.

6. “Traditional Neighborhood Development — street design guidelines” by ITE, June 1997.

7. “AASHTO (2001) and the Urban Arterial” by Peter Swift. 2003. From Swift and Associates, Longmont CO.

8. “Traditional Neighborhood Development — street design guidelines.” NCDOT Div. of Hwys. TND Guidelines. 8/00. Raleigh NC.

8. “Street-type matrix” Portland OR. 10/02.

9. “Changing the Residential Street Scene” by Eran Ben-Joseph. APA Journal Autumn 1995.

10. “Neighborhood Street Design Guidelines” Vancouver WA SE Neighborhood Traffic Mgmt Plan. 10/03.

11. “Mobility-Friendly Street Standards for Delaware” by Reid Ewing. Urban Street Symposium Conference Proceedings: Dallas. 12/00.

12. “Urban Design Guidelines.” City of Raleigh NC. Draft 6.6.01

13. “Central Florida Mobility Design Manual.” Prepared for Lynx by Glattening, Jackson. 1994/1995 edition.

14. “The Hidden Design in Land Use Ordinances.” Edited by Paula M. Craighead. March 1991.

15. “Twelve Steps Toward Community Walkability” by FDOT Safety Office. Pedestrian Facilities Planning and Design Training Course. Undated.

16. “Design Highlights: Traditional Neighborhood Development District” by Tunnel-Spangler & Associates for the City of Oak Ridge TN. 11/01.

 

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Filed under Bicycling, New Urbanism: Timeless, Traditional, Walkable Design, Sprawl and Suburbia

The Merits of New Urbanism

By Dom Nozzi, AICP

The standards and principles of new urbanism are designed to make areas more livable, more vibrant, and more people-oriented, and to build community pride in the city and the work of its developers.

The people-oriented, traditional areas of the city share a number of desirable characteristics that provide us with many benefits. We should strive to preserve, celebrate, encourage and emulate how these areas are designed because of such benefits. For example, a traditionally designed city provides the following benefits:

Gives people without access to a car, such as children, the elderly, and the disabled, more safety and independence in their world.

Enhances urban livability, which reduces the desire to flee to the suburbs, which, in turn, reduces the pressure for costly sprawl and strip commercial development.

Substantially reduces government and household costs — especially because of the enormous savings in the building and maintaining of road infrastructure, and the purchase and maintenance of cars.

Reduces the need for travel.

Helps retain historic structures instead of replacing them with parking or large suburban retail “boxes””

Features streets designed to slow traffic. It increases travel choices and reduces the length and number of vehicle trips.

Makes neighborhoods more memorable and dignified.

Contains structures built for permanence, instead of structures designed, as too many contemporary structures are, for a short-term “throw-away” life.

Integrates income groups by mixing housing types and providing a public realm available to all incomes.

Makes walking feel more enjoyable.

Is not characterized as much by strip commercial visual blight.

Increases citizen access to culture.

Creates a good environment for smaller, locally-owned businesses to become established and to operate in.

Puts “eyes on the street” and promotes “citizen surveillance” of public places where citizens watch over their collective security, crime is reduced, as are public law enforcement costs.

Stabilizes, reinforces the identity of, and improves the value of nearby older neighborhoods.

Preserves and promotes community character.

Promotes neighborhood and community self-sufficiency and, therefore, sustainabilty.

Reduces per capita gasoline consumption and air pollution.

Coupled with regulations that are designed to promote and preserve its features, restores the traditional citizen hope and expectation for a better future with each new development in the city, and, in so doing, reduces the extreme polarization between developers and neighborhoods.

Provides affordable housing options.

Creates a sense of place, a sense of community, a sense of belonging and restores civic pride and place-based loyalty.

Strikes a balance between the needs of the car and the needs of the pedestrian. It creates a pedestrian ambiance and interesting pedestrian features, and makes the pedestrian feel safe, convenienced, and comfortable.

Creates a good environment for smaller, locally-owned businesses to become established and to operate in.

Increases transit viability, primarily through density, access, traffic calming, community-serving facilities, compactness, mixed use and pedestrian amenities.

Currently, developers are often reviled and their developments feared. This is manifested in the contemporary epidemic of NIMBYs (not in my backyard), NIMTOOs (not in my term of office), BANANAs (build absolutely nothing anywhere near anything), and NOPEs (not on planet earth). Largely, these attitudes have emerged because since WWII, developers and cities have sought to make cars instead of people happy.

Typically, American suburbs are characterized by this design. Suburban design features:

Large setbacks that are inconvenient for pedestrians and fail to define a comfortable public realm

Large parking lots in front of buildings

Large street blocks with no cross access or connecting streets

Buildings with their backs or sides turned toward the street. Instead of an entrance or windows, the pedestrian is confronted with blank walls, air compressors, dumpsters, and long walks to the building

Pedestrian-hostile features that are designed to promote car use, such as drive-throughs, single-use zoning, segregation of land uses, and “armoring” with fences and walls

To make Gainesville a safer, more livable place, and to increase citizen pride in its developments, the new urbanist standards are designed to primarily promote the health, safety, and welfare of pedestrians, while still accommodating the needs of the car. More specifically, the design is intended to make the pedestrian feel:

Safe and secure

Convenienced

Pleasant and comfortable

With enhanced safety, livability, civic pride, and visual appeal in these older parts of the city, the city will establish an important engine in job recruitment and a strengthened tax base. A downtown that adheres to these standards will be a city that provides an important incubator for new, entrepreneurial, locally-owned small businesses and entry-level job opportunities. A healthy downtown also protects the property values of surrounding residential areas.

Some Principles of New Urbanism

Build-To Line

Overly large setbacks are inconvenient and unpleasant for pedestrians. They are inconvenient because they can significantly increase walking distances from the public sidewalk. They are unpleasant because they prevent the pedestrian on the public sidewalk from enjoying the building details and the activity within the building. In addition, they prevent the building from contributing to an intimate, pleasant, comfortable street wall, which harms the sense of place and makes the pedestrian feel as if she or he is in “no man’s land.” Buildings pulled up to the street sidewalk have more of a human scale. The intent of a build-to line is to pull the building facade up to the street to abut the streetside sidewalk. By doing so, building facades along a block face will be aligned to form a street wall that frames the public realm, while retaining sufficient width for people to walk, and sufficient space to provide a formal landscape created by the shade of street trees. The street wall shapes the public realm to provide a sense of comfort and security for the public space.

Building Height of At Least Two Stories

“Low-slung” one-story buildings are more appropriate in low-density residential areas designed for motor vehicle travel. They reduce the density and intensity needed to make transit, walking, and bicycling viable, and typically are too low in profile to form a desirable, intimate, comfortable public realm with facing buildings across the street. They also reduce the opportunity to create mixed-use buildings containing, typically, both commercial and residential uses. Low-rise multi-story buildings two to five stories in height are an important component of the compact, walkable city. The building profile forms the desired street wall and the additional stories allow the establishment of the number of residents needed for a viable urban neighborhood.

Parking Located at the Rear or Side of Building Instead of in Front

Parking areas located in front of buildings are inconvenient and unpleasant for pedestrians. They are inconvenient because they significantly increase walking distances from the public sidewalk. They are unpleasant because they often make for hot expanses of areas to walk in, prevent the pedestrian on the public sidewalk from enjoying the building details and the activity within the building, and increase safety problems since pedestrians must dodge cars in the parking area. In addition, they prevent the building from contributing to an intimate, pleasant, comfortable street wall, which harms the sense of place and makes the pedestrian feel as if she or he is in “no man’s land.” Buildings pulled up to the street without intervening motor vehicle parking have more of a human scale.

Hidden Trash and Recycling Receptacles and Loading Docks

Trash and recycling receptacles and loading docks typically provide an unsightly appearance and an odor problem for pedestrians. In addition, improperly located and improperly screened receptacles and docks can cause noise problems for nearby land uses when the receptacles and packages are being loaded or unloaded. Therefore, they should be located as far from public sidewalks as possible and screened from view.

Sidewalks Sufficiently Wide and Aligned for Convenience

Sidewalks, when properly dimensioned and maintained, can provide the pedestrian with a pleasant, safe, and convenient place to walk. Sidewalks that are too narrow are inconvenient, especially in areas with large volumes of pedestrians, pedestrians walking side-by-side (which requires a minimum sidewalk width of five feet unobstructed), and people using wheelchairs. In addition, sidewalks that must wrap around large block faces are a serious impediment to pedestrian convenience.

Building Oriented to the Street, Instead of Turning Its Back to It

A successful commercial establishment is designed to provide convenience for customers by minimizing walking distances from public sidewalks and nearby buildings. Rear or side entrances, or entrances oriented toward a parking lot, make travel highly inconvenient for pedestrians and transit users. Such a design also cuts the building off from street life. In addition, a building with its main entrance directed away from the primary sidewalk and street “turns its back” to the public realm, reduces urban vibrancy, and is harmful to promoting street life. When a building is located at an intersection, the most convenient entrance is usually abutting the public sidewalks at the corner of the intersection. Often, the most convenient sidewalk is formally aligned diagonally and aligned straight to minimize walking distance.

Facade Treatment Creates Interest for Pedestrians

All building shall be designed to provide interest for pedestrians. Long expanses of blank walls tend to be boring and unattractive for the pedestrian. In addition, windows attract pedestrians, which act as a security system for the business. Buildings without such relief and interest tend to create a “massive scale”, and makes the public realm impersonal. Such an appearance is inconsistent with the “human-scaled” and pedestrian-oriented character of the a traditional area of a city, and inconsistent with a city intent to restore such character to the traditional city area.

Hidden Outdoor Mechanical Equipment

Outdoor mechanical equipment, such as heating or AC units, when improperly located on a site or improperly screened, can contribute to noise problems and create visual blight.

Formal Landscaping

In the traditional, pedestrian-oriented areas of a city, landscaping should be used both to soften the “hardness” of the urban area for the pedestrian, and make the pedestrian feel more comfortable by providing cooling, reducing glare and helping to form public spaces, “outdoor rooms,” and street corridor edges. Such formality of landscaping adds dignity to the traditional area of a city, instead of a chaotic one, thereby inspiring a sense of civic pride.

Properly Scaled Lighting

Lighting can often detract from the intimate, pleasant, romantic character a city seeks to promote in the traditional, pedestrian-oriented areas of a city. But lighting designed for cars tends to be not human-scaled. Lights on tall fixtures cause light pollution by casting light into areas not needed by pedestrians. In addition, the lights present a poor, bleached out atmosphere as the pedestrian views an area from afar, and hides the nighttime sky completely. A new urbanist, pedestrian-oriented street lighting design features shorter and more numerous light fixtures and structures.

Prohibited Auto-Oriented Uses

Certain uses are oriented toward or designed to attract motor vehicles, and therefore contribute to danger, visual blight, inconvenience, and lack of human scale for pedestrians. Therefore, such uses are not compatible with the a people-friendly downtown area.

Alleys

Alleys allow the developer to place garages, driveways, waste receptacles, and overhead utilities in a less conspicuous location away from the public street and therefore less likely to detract from the pedestrian ambiance of the neighborhood. Alleys also provide an additional location for emergency vehicles to gain access to a building, and a relatively safe place for children to play.

Front Porches

When they are set back a modest (“conversational”) distance from the sidewalk, porches allow persons to sit on their porch and interact and socialize with their neighbors. They therefore add safety (by putting “eyes on the street”) and friendliness to the street. As a result, porches contribute to an enjoyable walk by pedestrians in the neighborhood.

Narrow Streets

Narrow streets force cars and trucks to travel slowly through the neighborhood, which significantly contributes to neighborhood safety, low noise levels, low traffic volumes and, therefore neighborhood livability.

Mixed Housing Types

Mixed housing types provide the neighborhood with a mixed income environment, since the mixed types provide a range of housing affordability. Mixed housing types enable lower income workers to live within walking distance of their jobs, instead of creating traffic problems by being forced to commute by car to their jobs.

Transit Links

When a neighborhood contains — or is near — safe, pleasant, and convenient bus stops, a larger number of trips are made by bus, which reduces excessive neighborhood trips to and from the neighborhood by car. This provides more transportation choice, enhances neighborliness, and reduces household transportation costs (every car a household can shed saves the household the equivalent of the monthly home mortgage payment on a $51,000 house, at 10 percent interest).

On-Street Parking

Buffers pedestrians from vehicle travel. Narrows the street in order to slow traffic to a safer, more livable speed. Provides convenient parking locations for nearby businesses. Allows businesses and residences to reduce the amount of off-street, on-site parking, which reduces the “heat island” effect and enhances urban vibrancy by improving the public realm.

Mixed Use

Reduces trip distances to the point where walking, bicycling, and bus trips are much more feasible for a number of different types of trips. Adds to neighborhood and urban vibrancy by increasing the number of places people can meet — such as a pub, on the way to work or a civic event, a grocery store, a fitness center, etc. Provides children with more of an awareness of community land uses other than parks, residences, and schools.

Resessed Garages

Enhances the neighborhood walking environment for the pedestrian. Houses appear people-oriented and interesting to walk along, instead of sending a strong message that “a car lives here.”

Narrow, Smaller Lots

Provides a more compact, walkable arrangement of houses. Provides a more pleasing alignment of houses along the streetside sidewalk, which enhances civic pride in the neighborhood and makes the residential street seem more “cozy.” Blocks are reduced in size, which makes the neighborhood more walkable. Narrower lots increase the frequency of front doors along the street, which greatly enhances the vibrancy of the street. Houses appear to be associated in a neighborly way, instead of isolated and cocooned from the neighborhood. Smaller lots also make home ownership in such a subdivision more affordable. In addition, the higher, yet livable, density that smaller lots provide makes transit more viable.

Connected Streets

Makes walking, bicycling, and using the bus more feasible by significantly reducing trip distances and increasing the number of safe and pleasant routes for such travellers. Provides motorists and emergency service vehicles with more “real time” route choices. A route that is impeded or blocked can be avoided in favor of a clear route, which is not possible on a cul-de-sac. In combination with the fact that connected streets distribute vehicle trips more evenly, real time route choices on connected streets reduce congestion on collector or arterial roads. As a result of this distribution, there is little or no need for neighborhood-hostile collectors or arterials, which, because of the volume and speed of vehicle trips they carry, are unpleasant for residences to locate along.

Terminated Vistas

A concept in which a prominent building is placed at the “visual termination” of a street. Provides dignity and prominence to important civic buildings, such as post offices, libraries, city halls, churches, convention centers and performing arts centers. Sends the message that the building is an important place for the community. In addition, terminated vistas make walking more pleasant by giving the pedestrian a “goal” to walk toward. The walk therefore does not seem endless. It also provides an impressive view to strive to reach. Such vistas also make trips more memorable by helping to orient a person as to their location in the community.

Livable, higher densities

The conventional way in which we address land use conflicts is to put distance between conflicting activities, and minimize the number of dwelling units per acre. But this does little to encourage land users to reduce the damage they do to the environment. Also, by segregating uses, we increase the amount people have to travel by car, which itself reduces the quality of the urban and natural environment.

By contrast, the more compact, higher density “new urbanist” development reduces trip length; and makes bicycling, transit, and walking more viable. For these reasons, compact development generates about half as much vehicle travel as does sprawl development, making such a land use strategy one of the most effective in reducing auto dependence.

Minimum densities necessary for a viable bus system are approximately eight dwelling units per acre. Newman and Kenworthy indicate that only when densities exceed 7,000 to 8,000 persons per square mile (Gainesville’s density is currently 2,000 per square mile) do mixed land uses and shorter travel distances become predominant enough to significantly reduce auto dependence. These researchers note that a dramatic reduction in per capita gasoline consumption occurs when population density reaches 12 to 16 persons per acre. “Low density land use ensures almost total dependence on automobiles, enormous travel distances, no effective public transit, and little possibility of walking or [bi]cycling. Below five or six people per acre, a city almost ceases to exist, and requires enormous transportation energy to hold the scattered parts together.”

A recent study found that distance is the most widely cited reason for not walking more often, thereby showing the importance of compact development as a strategy to encourage walking. People living in high-density areas are much more likely to walk than those living in low-density suburbs, even when suburban trips are less than one mile (note that higher population densities seem to be more strongly correlated with higher walking rates than does a compact land use pattern). There also seems to be a correlation between the shorter commute distances associated with compact cities and higher bicycling rates. Compact, mixed-use development has been cited as much more likely than improved bicycle facilities, congestion fees, or fuel price increases to recruit motorists to bicycling.

Residential development that averages 14 dwelling units per acre requires half as much road mileage to serve vehicle trips than development at 3.5 dwelling units per acre. Another study found that for each doubling of residential density, vehicle miles traveled is reduced 30 percent. Thus, if the population of an area doubled due to infill development, vehicle miles traveled would probably increase by only 40 to 60 percent, rather than the 100 percent it would increase if the population increase occurred in dispersed suburbs.

A recent study has confirmed that the shift from car trips to transit and walking does not occur until certain job and housing densities are achieved. For work trips, the thresholds are 50 to 75 employees per gross acre, or 12 dwellings per net acre. For shopping trips, it is 75 employees per gross acre and 20 dwellings per acre.

One way to increase development densities is to remove land development policies that reduce development densities, such as minimum lot size zoning and minimum parking requirements.

Public service vehicles scaled small enough so that they do not dictate unsafe, wide streets

New urbanism encourages the use of public service and emergency vehicles (such as fire trucks) that are scaled to be compatible with neighborhoods. Increasingly, such vehicles are quite large, and their size often dictates rather wide streets and unsafe turning radii. Yet studies show that the dangers of such street design typically far outweigh the safety benefits that larger streets and turns will provide for emergency vehicles. In general, this is because the probability of traffic injury or death due to over-sized streets is much higher than the chance that injury or death would be averted because the emergency vehicle can shave a few seconds off of a trip. Therefore, smaller service vehicles can help a City keep average neighborhood vehicle speeds lower, make the streets safer and less noisy, make the neighborhood more walkable and, in general, more livable and sociable.

Streets and sidewalks straight, not curvilinear

Streets are more memorable and less disorienting when they are straight. They are more dignified, and can be terminated with a prominent vista. It is important that sidewalks be straight, since pedestrians have a strong desire to walk the distance that provides the minimum trip length. Curving sidewalks promote the creation of “cow paths,” as pedestrians take short cuts along their route. In general, curvilinear sidewalks are only appropriate when needed to avoid a large tree or other important physical feature, or in an area in which most pedestrians are walking strictly for optional recreation or exercise. This is generally not the case in an urban area, where almost all trips are utilitarian. Mostly, curving sidewalks are intended to improve the view of motorists driving along a road, and provide no important benefits for the pedestrian.

One-quarter mile walking distance

It is generally recognized that the convenient walking distance ranges up to one-quarter mile, or roughly a five- to ten minute walk. It is therefore important that for a neighborhood to be walkable, most homes should be within one-quarter mile of public parks, schools, civic buildings, retail, office, and various forms of culture. The one-quarter mile design yardstick also enhances the viability of transit.

Short, walkable block faces

In general, a neighborhood or commercial block face length should not exceed approximately 500 feet. Longer blocks tend to create inconvenient walking distances. When long blocks must be created, they should be shorted with cross-access walkways.

Ground-floor retail. Offices and residential above.

This form of mixed use enhances vibrancy and provides more affordable housing choices. It reduces the need for trips by car, since employees of the retail establishment can live above the shop. It is important that such “vertical mixing” of uses not place residential on the first floor, since it is disruptive for the residence when users of the office or retail must walk through the residence. It is also important that such mixed use include retail on the first floor so that more energy and interest is at the street level – -thereby benefiting pedestrians.

Eyes on the street. Citizen surveillance

Law enforcement agencies increasingly see the merits of citizen policing, in which citizens are able to watch out for their collective security. Such “eyes on the street” are promoted when buildings, windows, entrances and porches are near the street and sidewalk. Citizen surveillance is also promoted when the neighborhood or commercial areas are designed for regular, frequent pedestrian activity. Areas without pedestrian activity are areas where illegal, inappropriate, or unsafe behavior can occur more easily since there is no one to observe the deed and report it or intervene.

Diagonal usually the shortest walking distance

In general, the shortest walking distance is a diagonal route. Frequently, sidewalks are designed with right angle turns, which increases the walking distance and increases the likelihood of “cow path” shortcuts.

Centrally-located schools, parks, squares, civic w/in walking distance of most homes

When schools, parks, squares, and civic buildings are within easy walking distance of most residents, a sense of community and neighborliness is promoted, and vehicle trips are greatly reduced. If children are able to walk to school or a park, such areas can become social and recreational gathering places for students, because they are able to go to the school or return home on their own, as opposed to being required to leave when the bus leaves at the end of the class day.

Parks, squares and civic uses are more frequently used when residents have easy, non-vehicular access to them. When centrally located, they become the focal point of the neighborhood, and maximize the number of residences that are within walking distance.

Square street curbs

Square street curbs provide more safety for pedestrians, and provide a more attractive, urban appearance for the neighborhood.

Modest curb radius

A larger curb turning radius at an intersection or a parking area ingress and egress point allows vehicles to negotiate a turn rapidly, whereas a smaller radius forces a vehicle to slow down. Conventional traffic engineers often prefer a larger radius for vehicle convenience and curb protection, but such a radius makes life more inconvenient and dangerous for pedestrians. A larger radius also significantly increases the distance for crossing the street, which exposes the pedestrian to more danger from moving vehicles.

Note that large garbage trucks or delivery trucks or buses or fire trucks should not dictate the design of neighborhood curb radii. To do so is equivalent to obligating an architect to increase the size of the front door opening so that an overly large TV set can be brought into the house. No, the correct solution is to request that service and emergency vehicles be scaled for neighborhoods…

 

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Filed under Bicycling, New Urbanism: Timeless, Traditional, Walkable Design, Parking, Sprawl and Suburbia, Traffic Congestion, Visioning