Why Stapleton residents fear their streets

To get things built, new urbanist designers often must compromise their design ideals. Frequently that means taking what we love about New Urbanism and trying to squeeze it through conventional traffic engineering standards and mindsets. The end product is typically a hybrid; it possesses some of the qualities that make New Urbanism desirable but is diluted by conventional demands such as swift automobile circulation.

Living for the last three years in Stapleton, the Denver area’s largest new urbanist development, I’ve been confronted by the discrepancy between the ideal, on the one hand, and the impure built reality, on the other. When it comes to New Urbanism, Stapleton looks the part with beautiful, tree-lined streets, great architecture, mixed uses, neighborhood schools, and an abundance of parks, greenways, sidewalks, and bike lanes. 

However idyllic the transportation system appears to be, cars moving at very high speeds are not uncommon, and driving is more prevalent in Stapleton, a Denver Regional Council of Governments survey found, than in three of Denver’s older, more established neighborhoods—Cherry Creek, East Colfax, and the Highlands.

Handling the disconnect

I came to realize that if we look at Stapleton’s street designs, street network, and how people actually use the transportation system, we might be able to figure out how new urbanists can better handle the disconnect between new urban transportation design ideals and conventional engineering solutions—and the insidious implications of those disconnects.

There will never be a single, cookie-cutter approach to designing a transportation system consistent with New Urbanism’s ideals. However, we can get a sense of how to proceed by noting that most new urbanists do subscribe to a few underlying principles. Among them: an insistence on narrow streets, supported by a compact and connected street network.

Stapleton was intended to embody such thinking. The 1995 “Green Book,” the redevelopment plan for the 4,700 acres of former airport land, states that one of the project’s primary transportation goals is to connect the huge site to the existing gridded street network outside its boundaries. The document even shows historical maps of the city’s original 1920s street grid expansion plan—reinforcing the underlying intent of fully linking Stapleton to the surrounding grid.

As it developed, Stapleton ended up with a street network that’s relatively compact. Though the blocks aren’t nearly as small as those in downtown Portland, Oregon, which has a grid of 200-by-200-foot blocks, Stapleton’s network has a compactness similar to that of Berkeley, California—a highly walkable and bikable city.

A compact street network, however, is not necessarily a connected network.  On Stapleton’s perimeter, the street network is not well linked to the surrounding gridded older neighborhoods. Internally, limited connectivity results partly from Stapleton’s abundance of beautiful parks and greenways. The parks and greenways provide direct routes for pedestrians and cyclists, at some sacrifice of vehicular circulation.

Consequently, Stapleton, like many new urbanist communities, has a network that is well connected internally, but has limited connectivity to the surrounding city.

Such a layout provides plenty of ways to get around within the neighborhood, but it offers only limited connections to the areas beyond. A typical new urbanist development may be laid out like a single one of the smaller grids in that diagram.

One of the things that makes Stapleton interesting to study is its size. With over 12,000 residents already and with more than 30,000 inhabitants expected at build-out, Stapleton dwarfs most other new urban communities. As a result, a big community like Stapleton consists of many such neighborhoods. Therefore the major streets are not just at the edges of the community; they also run through the community, bisecting it.

Unfortunately this large size, in combination with the limited street connectivity, leaves us with only a handful of streets running from one end of Stapleton to the other. Martin Luther King Jr. Boulevard (MLK) is the only street that provides an east-west vehicular route. Most of Stapleton’s north-south movement is concentrated onto Central Park Boulevard. The design intent might have been to limit the though movement of traffic on residential streets (although I’d argue there are much better ways of accomplishing this); the disadvantage is that all of the through traffic must find its way onto a select number of streets

"Predict-and-provide"

Most regions and municipalities, including Denver, predict future traffic demand based upon past trends and estimated traffic growth. In what is commonly known as the “predict-and-provide” approach, a conventional traffic engineer figures out how many vehicles will want to use a particular street 20 or 30 years in the future, and then tries to provide enough capacity to accommodate them all. In Stapleton, almost all the cars need to be accommodated on a very limited subset of arterial streets such as MLK and Central Park Boulevard.

Though current traffic counts on Central Park Boulevard are less than 12,000 vehicles per day even after a new direct connection to I-70, the future traffic demands (as forecast by the Council of Governments’ 30-year regional travel demand model) are predicted to be 30,000 a day. The conventional traffic engineer thus designs the street to accommodate that volume—without ever asking whether it makes sense to run 30,000 vehicles through these neighborhoods.

The reality is that the predicted volumes are typically based on a business-as-usual approach to transportation and land use—one in which we not only prioritize cars over other modes but even more insidiously, we consider the movement of cars through a neighborhood to be more important than the neighborhood itself. Why do many engineers continue to design under this paradigm? Often it’s attributed to a fear of congestion or of hindering economic activity. But only cities that are low on economic vibrancy have any chance of eliminating congestion. In fact, the projected level of vehicle demand will be realized only if we choose to accommodate it and continue following the same self-perpetuating, auto-oriented travel behaviors and land use patterns that have defined us for the last 50 years. 

Unfortunately for Stapleton, the arterials were designed with long-term projected vehicle demand numbers in mind, as opposed to designing for an appropriate level of traffic that fits both the context and the vision of the community. Central Park Boulevard is best described as a parkway with two lanes of through movement separated by a 50-foot raised median. Each direction also includes a bike lane, a parking lane, and turn lanes at certain intersections. Most of MLK has two travel lanes in each direction (one segment within Stapleton has three travel lanes in each direction), with on-street parking along certain stretches but no bike lanes. The speed limit is 30 mph on Central Park Boulevard. It alternates between 30 mph and 35 mph on MLK. Both streets are far too large for their current traffic volumes.

Speeding on the streets

Much current research suggests that over-designed streets lead to high vehicle speeds. That is exactly what we are finding at Stapleton. Drivers have been shown to violate the speed limit more than 18 percent of the time on MLK and more than 35 percent of the time on Central Park Boulevard. On both streets, cars commonly exceed 50 mph. On MLK, some race through at more than 70 mph. The result: these streets act as significant barriers between various neighborhoods.

Smaller streets suffer from excessive, code-mandated street widths. Local streets in Stapleton are generally designed for two-way traffic with on-street parking on both sides. Such a cross-section, according to the City’s regulations, typically requires a minimum 32 feet of width (although this may be reduced to 30 feet if the street meets a handful of criteria and receives public works approval), with a 60-foot right-of-way.

Collector streets, also with two lanes of travel plus space for on-street parking on both sides, must be 40 feet wide (but can be reduced to 36 feet if meeting a similar set of criteria), with a 64-foot right-of-way. In Stapleton, local streets tend to be either 30 or 32 feet, while collector streets are all 38 feet across (even though land uses on many of the collector streets are identical to those on the local streets). 

Safety studies have shown that wide streets are much more hazardous. On 38-foot-wide Beeler Street (including sparsely used parking on both sides), more than 63 percent of drivers were found to exceed the speed limit. Some went more than twice the posted limit. Similar results were found along 26th Avenue, where a 30-foot cross-section accommodates two-way traffic and only one parking lane. In contrast, on Willow Street, where two-way traffic and on-street parking on both sides have been fit into 30 feet of pavement, only 3 percent of drivers exceeded the speed limit, and no drivers were found going more than 40 mph.

Besides endangering pedestrians and cyclists, high vehicle speeds affect people’s perception of safety, which often exerts an even greater impact on their travel decisions. A troubling condition can be discerned from a recent Front Range Travel Survey of more than 12,000 households across the region. Data from this study shows that both Stapleton and Lowry, another new urban neighborhood, lag well behind three older, more established neighborhoods—Cherry Creek, East Colfax, and the Highlands—in walking, biking, and transit mode shares. In both Stapleton and Lowry, more than 90 percent of employed people drove to work. While it is expected that transit use among Stapleton residents will likely increase once the east commuter line rail is completed in 2015, the reliance on driving and the low walking and biking mode shares for Stapleton are disappointing.

One vivid illustration of these problems: Denver Public Schools decided to provide buses for students to cross Central Park Boulevard, even in cases where they do not meet the minimum distance typically required to be eligible for bus transportation. A mother interviewed on Colorado Public Radio said that instead of crossing Central Park Boulevard on foot, she walks her children “about eight blocks to the east to catch the bus” even though “the school is eight blocks west.” It is impossible to declare a new urbanist community successful when situations like those exist.

What now?

Current thinking is that Stapleton needs more signage, more traffic lights, and better police enforcement. But those don’t solve the problems. We need a more systematic resolution to excessively wide local and collector streets and over-designed arterials.

For Stapleton, network-level solutions—such as better connecting to the urban grid not just within Stapleton but also to the surrounding neighborhoods—are possible but exceedingly difficult to implement once a place has been constructed. At the scale of the individual street, there seems to be a straightforward recommendation: make narrower streets. Reducing capacity on the arterials seems like low hanging fruit, but wholesale changes aimed at narrowing streets throughout Stapleton would be an enormous and expensive undertaking.

Instead of waiting, some residents might want to follow the lead of the Stapleton resident who routinely parks his truck nearly four feet from the curb on one side of high-speed Beeler Street and displays a sign attached to a parked trailer on the other side urging, “drive like your kids live here.”

Whatever the future holds for Stapleton, other communities should learn from Stapleton’s shortcomings, understand the pervasive influence of conventional traffic engineering solutions, and try from the outset to build better networks made up of narrower streets. Focusing on community goals, such as those set forth in the original Stapleton vision, and looking for ways to better reconcile new urbanist transportation design ideals with the conventional traffic engineering mindset would go a long way toward ridding ourselves of unsafe, unmanageable streets.

These transportation problems are beginning to percolate not through just Stapleton but other large-scale new urban developments as well. Unless such problems are addressed, not only will we fail to achieve the supposed transportation benefits of New Urbanism; our designs will be relegated to a niche market, never truly fulfilling their promise.