Faced with questions of, can we count on people biking and walking if places are built with these “modes” in mind, cities historically turned to planning tools that, it turns out, failed to provide a definitive “yes.”
City planners have been hamstrung, until recently, by inadequate tools for predicting how, for example, an area with a high Walk Score translates into where and when people decide to walk, bike or take transit.
Enter the Transportation Research Board, an arm of the National Academy of Sciences, whose "Estimating bicycling and walking for planning and project development" is a guidebook for cities that links variables—like road size and socio-economic traits of users—to higher rates of car-free choice making.
The report is technical, but it affirms that places with “high walk accessibility” do see increases of feet on the street. Arlington, Virginia and Seattle, Washington, for example, where they created computer models that drill down to the block level are better at pinpointing why people choose to walk than Metropolitan Planning Organizations (MPOs) using models that stop at the Census tract.
In essence, these experiments are similar to Walk Score, but with more rigorous standards, more data, and better mapping tools.
The proof is in the results. At the top end of walk and transit scores—like Arlington’s Rosslyn-Ballston corridor where the Orange Line commuter rail connects to D.C.—trips made by transit increased from 30 to 50% and projected “walk mode split” for work trips increased from 1% to 14%. This corridor has zoning that encouraged significant compact, mixed use development and has paid attention to biking trends by investing in infrastructure like a wayfinding system.
What makes people walk?
“Perhaps as important as the effect of walk-accessibility on walk mode share is the effect that higher walk-accessibility has on transit share, particularly at the destination end,” TRB concludes. “This may be due simply to destinations being more walk accessible to transit users, but may also provide evidence that travelers are more likely to use transit if they do not have to be dependent on personal vehicles once they reach their primary destinations.”
More MPOs should move to adopt these models because they offer metro areas a fine-grain view of who walks and what might be motivating them. Factors such as geography, age, and income matter the most. Seattle and Arlington looked at not only where people were going, but also, how close did they live to a bus stop, how many cars were in the household, and what form of transit was available at their destination.
“Because research shows that households residing in settings (that are) more transit and walk friendly own fewer vehicles, more regional models are beginning to incorporate context factors when predicting household vehicle ownership (see Atlanta, Austin, Los Angeles, and Portland).”
Fewer cars / more destinations
While the report cautions that a specific “mode split” number (or how many will walk and bike instead of drive) is hard to predict, it points to which factors matter most when people are making a choice between driving or not. It may prove compelling enough to shake up the planning industry’s more “facility” driven model of build it and they will come, they conclude.
For example, the new models account for the behavior of people in walkable neighborhoods—they make more “simple tours” (a single stop)—where those in more auto-centric areas tend to gang up stops in a “complex tour.” Current models don’t consider that possibility or that people will walk and bike outside of their tract.
It also showed that both the high and low end of the income scale in the U.S. have the best rates of walking, albeit, the former out of necessity and the latter for recreation. The biggest impediment to walking and biking is access to places to go, followed by feeling safe, which translates into fewer times pedestrians have to mix with high vehicle traffic. They are even finding that sidewalks are less important in residential areas as they are around commercial districts.