Tag Archives: block length

Essential Ingredients for a Walkable, Compact Town Center


By Dom Nozzi

December 20, 2013

I attended a joint citizen board meeting regarding “Sustainable Streets and Centers” in Boulder, Colorado. Here are my thoughts about necessary strategies.


  • Boulder has adopted a clear vision for one or more newly emerging walkable, compact centers in locations such as East Arapahoe Road, Colorado Street, and East Boulder, and intends to use effective tactics to induce the creation and sustainability of such centers.
  • People that desire to live in walkable, compact living arrangements seek a setting that is conducive to such a lifestyle. That setting features low-speed, narrow and human-scaled streets and intersections, very short walking distances to most destinations, buildings pulled up to the sidewalk to create enclosure, and a vibrant experience (in contrast to deadening expanses of parking and large building setbacks). The market for higher density housing will be very weak and unsustainable if such a walkable setting is not provided.
  • 15-minute neighborhoods are an important Boulder objective, which will require the creation of a relatively large number of centers.
  • The objective for centers is a drive to rather than drive through experience, a park-once setting, and a design that makes the pedestrian the design imperative.

General comments

First, strive to use words that resonate and are understandable to non-professional Boulder citizens. Terms such as “multi-way” or “activity center” or “alternate modes” or “corridor” are confusing, uninspiring, and negative. Second, when visioning or seeking comments from citizens, it is important that citizen comments be guided and informed by skilled design professionals (such as Dover-Kohl) who are skilled in presenting information in an understandable, inspiring way (particularly through use of quality graphics). Third, existing housing, employment, or land use patterns should not necessarily dictate visions if such patterns conflict with Boulder objectives. Fourth, the needs or convenience of regional commuters should not trump the low-speed, vibrancy, pedestrian scaled needs of Boulder’s centers.

Toolbox of Strategies that are Essential in Creating a Walkable, Compact Center

(somewhat different toolboxes are needed for other lifestyle zones – “transect zones” – in Boulder)

Land Development Regulations:

  • Motor vehicle parking is behind buildings.
  • Shorter blocks via cross-access pedestrian ways between buildings.
  • Mixed-use zoning to reduce walking/biking distance, and increase 24-hour vibrancy and safety.
  • Relatively high residential densities and commercial intensities.IMG_3045
  • Remove any regulatory barriers to infilling existing parking with buildings.
  • Do not allow gas stations at intersections.
  • Convert parking minimums to parking maximums. Require that the price of parking be unbundled. Increase allowable shared use and leased parking opportunities.
  • Relatively modest building setbacks. At intersections, a sense of place is achieved by requiring buildings to abut the back of sidewalks.
  • Exemption from landscaping requirements.
  • Relatively small minimum lot sizes.
  • Relatively small signs required by the sign ordinance (to help signal a low-speed, pedestrian scaled setting).
  • Proactively overlay a street grid with small block sizes before development is proposed.
  • Do not allow fences to cut off non-street access to adjacent parcels. Fences used should not exceed three or four feet in height along a sidewalk.
  • Emphasize multi-family housing rather than single-family housing in centers and along major streets.
  • Consider requiring at buildings at least two-stories in height for more of a sense of place, a sense of enclosure, mixed use opportunities, and better adaptability to change over time.


  • Shorter street blocks (200 to 500 feet max).
  • When streets passing through the proposed center are 4 lanes or more in size, they need to be necked down (road dieted) to no more than 3 lanes.
  • Intersections must be kept relatively small in size so that they are pedestrian-scaled. No more than one turn lane in a given direction, relatively narrow travel lanes, and small turning radii.
  • Continuous left turn lanes are to be discouraged. Raised medians with turn pockets are to be encouraged.
  • Raised crosswalks when feasible and appropriate.
  • Street (including lane width) and turning radii dimensions are small and slow-speed.
  • Street lights should be pedestrian-scaled so that light bulbs are no more than 14 feet in height. Taller lights create a highway ambiance and induce higher car speeds.
  • Bus bays are inappropriate in a compact, walkable center due to loss of pedestrian scale and increased pedestrian crossing distance.
  • Sidewalks have straight, rectilinear trajectories rather than curvilinear, suburban trajectories. Curvilinear trajectories, by adding unnecessary distances to walking, are annoying and patronizing to pedestrians. They are mainly benefiting motorists, who obtain a more pleasing view as they drive along a street with curving sidewalks. They also increase the likelihood of dirt cowpaths being formed by pedestrians seeking the shortest route.
  • On-street parking is allowed and priced.
  • Consider visually prominent gateway features at the entrances to centers to clearly signal to motorists that they are entering a low-speed, walkable setting that requires attentiveness.


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Filed under Sprawl, Suburbia, Transportation, Urban Design, Walking

Cul-de-Sacs and the Ingredients to Make a Town or Neighborhood

by Dom Nozzi, AICP

What makes a town or neighborhood? How do we know that a place is designed to successfully create a town or neighborhood?

Recently, these questions came up for me when a friend of mine indicated that a new urbanist “town” in his Florida county was not really a town. He also indicated his fondness for disconnected cul-de-sac neighborhood streets (albeit linked with bike paths).

The Problem with Cul-de-Sacs

When I thought about what my friend had said, I first wanted to remind myself of the problems I have come to learn about in both my research and in my life experience with cul-de-sacs.

Studies show, overwhelmingly, that those living in disconnected cul-de-sac subdivisions drive significantly more car miles. Such residents therefore walk, bicycle or use transit significantly less than those living in comparable neighborhoods with connected, gridded street design (with relatively short street block lengths).

It is not a coincidence that the timeless, lovable, compact towns that were built when most people walked are also towns that, almost invariably, have connected, gridded streets with short block lengths. This is predictable, as a connected, gridded, compact street pattern is much easier to use by pedestrians, bicyclists and transit users (which were the primary forms of travel when such streets were built). Only a car-dependent society is able to tolerate disconnected, curvilinear streets.

As a result, I am not surprised that I know of no disconnected cul-de-sac subdivisions where a meaningful number are walking, bicycling or using transit.

Disconnected cul-de-sac subdivisions forces all residents to drive a car nearly everywhere for at least two important reasons: (1) cul-de-sacs result in substantially increased distances, as disconnected roads very often force you way out of your direction of travel (or force you to backtrack); and (2) because contemporary, “modern” cul-de-sac subdivisions almost never incorporate any shops or jobs in the subdivision. Consequently, even if the streets in a cul-de-sac subdivision are connected in the future by bike paths, as my friend suggests, the distances remain enormous.

Furthermore, by disconnecting streets with cul-de-sacs, nearly all car trips are forced onto a tiny number of major roads (called “collectors” and “arterials”). That means that even with a relatively small number of motorists, the roads quickly become congested and angry demands start emerging almost immediately from residents of cul-de-sac subdivisions to install turn lanes and additional travel lanes (further making bicycling and walking less safe).

Because all trips are forced onto a few large roads, it is extremely inefficient to spend huge sums of money to build smaller roads that hardly ever get used (except by the tiny number of houses fronting the cul-de-sac).

Inefficiencies are also created with such disconnected roads in the delivery of public services such as mail delivery, garbage pick-up, fire response, police response, and medical response. Providing these services becomes significantly more costly due to back-tracking and indirect routing that cul-de-sacs cause. One typical and almost inevitable result: the local government is forced to raise taxes to pay for the higher service costs.

When streets are connected and therefore without cul-de-sacs, by contrast, car congestion is much less likely as car trips are dispersed on several connected roads. That means, among other things, that road expenditures are much more efficient. We’re not spending huge sums to provide for two or three car trips each day.

As for connecting cul-de-sacs with bike paths, it’s a nice idea that most town planners earnestly call for when subdivision plans come in, but the reason that only one out of a thousand cul-de-sac subdivisions have such path connectors is that contemporary cul-de-sac subdivisions are catering to an isolationist, privatopia lifestyle where folks are TERRIFIED that bike paths will be used by homeless, criminal, drug-dealing terrorists. Such people would either not buy a home if the cul-de-sac subdivision had such paths initially installed (lending institutions might also not lend if such paths were proposed), or they would scream bloody murder if there were a proposal to retrofit the paths at the end of cul-de-sacs after the homes were built and occupied.

Given all of the above, cul-de-sac streets effectively isolate households from fellow citizens. Such isolation fits well with those seeking a “cocooned,” privatized lifestyle that turns its back on the public realm. Such places are typically where we find people spending every night in isolation in front of their Big Screen TVs, and never interacting with their neighbors. The design, in other words, is one where we find a collection of loners.

For all of the above reasons, it is not surprising that the State of Virginia has recently banned or at least strongly discouraged new cul-de-sac subdivisions.

What Are the Essential Elements for Creating a Town or Neighborhood?

By striking contrast to the disconnected, cul-de-sac subdivision, there are at least four features that must exist for the creation of a quality town or neighborhood.

  1. First, houses need to be within a short walking or bicycling distance of the most important regular tasks of the household. Those tasks (or trips) include jobs, shops, services, culture, public meeting places (such as parks, squares or plazas) and civic institutions.
  2. Places conducive to true towns and neighborhoods provide “Third Places” (think of a neighborhood pub, or the TV show “Cheers”). Neighborhoods and towns also provide “social condensers” and other features which nurture a sense of community and sociable conviviality and neighborliness. Sidewalks – the most common form of social condenser — are therefore found on both sides of most or all streets. Each day, people interact with many others in their vicinity, and regularly enough so that a resident typically knows a large number of people on a “first name” basis. As Jane Jacobs famously noted, lowly, unpurposeful and random as they appear, sidewalk contacts are the small change from which a city’s wealth of public life must grow.
  3. Neighborhoods and towns have connected streets with short block lengths, and the streets have low design speeds. Such design is essential for minimizing trip distances and maximizing travel safety, both of which are extremely important in inducing travel by foot, bicycle, and transit. The geographic size of the place and the design of its streets are such that it is safe, convenient and pleasant to walk, bicycle, use transit or drive a car to get to most or all of the important needs in one’s day-to-day life. By contrast, places without such street design tend to induce exceptionally high levels of car travel, which isolates people from their fellow citizens, increases travel dangers, and harms residential property values.
  4. Finally, residents of real towns and neighborhoods tend to know the boundaries of their town or neighborhood, which gives their place an identity. One result is the possibility of feeling civic pride, which is essential in creating the all-important desire to protect and improve your town or neighborhood.

Are cul-de-sac streets conducive to building towns or neighborhoods as I define these essential elements above? In my view, the isolating, inefficient, car-dependent world produced by cul-de-sacs create the antithesis of a “neighborhood” or “town.”

The vast majority of cul-de-sac subdivisions that have been built in America since the 1930s are unlovable, unsustainable and therefore doomed to have a short life before they are abandoned and bulldozed.

Well-designed places are those containing the four ingredients I describe above, and are likely to produce, in the long run, places we will love, protect and cherish.


Visit my urban design website read more about what I have to say on those topics. You can also schedule me to give a speech in your community about transportation and congestion, land use development and sprawl, and improving quality of life.

Visit: www.walkablestreets.wordpress.com

Or email me at: dom[AT]walkablestreets.com

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Filed under Sprawl, Suburbia, Urban Design, Walking