Mapping comfort: how psychological stress influences bike maps

פורסם: 8 בפבר׳ 2013, 12:23 על ידי: Sustainability Org   [ עודכן 8 בפבר׳ 2013, 12:24 ]
By Nathan Wilkes, City of Austin, February 7, 2013

At its core, the Green Lane Project is about transforming the way our streets are designed. With this change comes the challenge of representing our evolving bicycling networks in maps, both paper maps and the increasingly important array of online mapping tailored to bicycling. This post is part one of two, focusing on traditional printed maps. A subsequent post will look into web-based mapping tools.

So, what should be shown on a bicycle map? Accurate and clear representation of our ever-improving networks is a basic goal. Maps should provide helpful route-finding information that encourages people to pump up the tires and go for a ride. And besides being useful to riders, good maps help planners identify priorities and deficiencies in our networks to make bicycling better.

In a 2012 study Low Stress Bicycle Bicycling and Network Connectivity, Northeastern University professor Peter Furth and his team analyzed San Jose, CA’s bicycling network from the perspective of the rider, using psychological stress as the key measurement of the effectiveness of a given bike route. Their conclusion: bicycling in traffic is too stressful for most people on most trips they want to make. The researchers write:

For a bicycling network to attract the widest possible segment of the population, its most fundamental attribute should be low-stress connectivity. That is, providing routes between people’s origins and destinations that do not require cyclists to use links that exceed their tolerance for traffic stress, and that do not involve an undue level of detour.”

To measure something as seemingly subjective as bicycling comfort and stress, the researchers used GIS data on traffic speeds and volumes, roadway widths, bicycle facility type and other readily available metrics along with a healthy dose of local knowledge to rank each San Jose street on a scale from 1 to 4, with 1 being the most comfortable and 4 being the most stressful. 

The four levels are inspired by the popular scheme for classifying riders, developed by Portland planner Roger Geller. Level 1 is comfortable enough for children to ride alone; Level 2, based on Dutch bikeway design criteria, represents the traffic stress that most adults, or the “interested but concerned” will tolerate; Level 3 represents roads that the “enthused and confident” will use and Level 4 the 

stress that that only the select few “strong and fearless” will tolerate. In San Jose, only 5% of short trips (6 miles or less) can be made on streets ranked as low-stress (levels 1 or 2), which the study notes, largely accounts for the low levels of bicycle use observed. 

So, if traffic stress is a primary factor in the bicycle routes people choose (and their decision whether to ride at all), how do we show traffic stress on maps?

There are two common approaches to traditional bike maps. The first is the facilities approach where off-street trails, cycle tracks, buffered bicycle, bike lanes, (even wide curb lanes or signed bicycle routes in some cities!), and bicycle boulevards are all discretely represented. You can see this method used in Portland’s map legend below, but also used by the other green lane cities of Chicago, Memphis, San Francisco, Washington DC.

Portland’s bike map legend (right) using a facilities approach. Note that the color scheme clostly matches a stress-based heirarchy as seen in the Austin legends below.

The other approach is based on the experience of the cyclist, or level of comfort. This method is used in Austin. (Austin uses “level of comfort” on its maps, a more marketable term than “level of stress.”) The advantage of using levels of comfort to map streets is that it provides bicyclists with what they need to know to plan a route, and nothing more. The result is simple, intuitive maps that are not overly cluttered with jargon or technical details. The levels of comfort can be represented using a color map of green to orange (or red) to designate the most comfortable to least comfortable.

The hurdle in switching to this methodology is convincing committed riders who are well-versed in the language of bicycle infrastructure that the quality of the experience is more significant to most people than the configuration of paint and curbs on the roadway. A narrow bicycle lane on a busy high-speed street with heavy truck traffic can be a world apart from a wide bicycle lane on calmer street, yet both appear equal on a traditional bike map. In the end, map makers have to answer the question of who their target audience is and what information they need. In Austin, map makers believe in the “interested but concerned” narrative — that about 2/3 of the population are interested in riding a bike more often and would, if only they felt safer and more comfortable. Mapping bicycling experiences is part of the toolkit for making bicycling mainstream. 

In Austin, mapping levels of bicycling stress goes back to 1991, when the first bicycle map of the city was produced. From 1991 to 2010 as seen in the legend below, high-comfort (green) routes were calibrated to the “enthused and confident” — riders who are willing to tolerate a certain amount of traffic stress — and trails were given a separate unrated designation. In 2010 the map showed a coalescing network of “high-comfort” (green) routes largely comprised of bicycle lanes on arterials and low-stress quiet streets. In 2011 the highest-comfort level (still green) was recalibrated to align to the “interested but concerned,” with some on-street bike lanes no longer meeting the criteria for the highest level of comfort. The new approach resulted in a map that appears much more fragmented, reflecting that there is still a long way to go before most of the population is comfortable riding bikes on the streets.

Austin’s bike maps using predominately a level of comfort (stress) approach. 2010 Map legend (left) with trails not rated for comfort. 2011 Map legend (right) with trails renamed as seperated paths and at the top of the visual comfort hierarchy.



2010 Map (left) showing bicycle lanes on busy arterials in green. 2011 map (right) shows a fragmented green network with work to be done.


GIS Mockup of a facilities based map using the Portland legend (left) that has separate symbols for cycle tracks, trails, and calm local streets; and level of comfort (stress) based map using Austin’s legend (right) that makes these three pieces of infrastructure appear as part of the same network simplifying way-finding for low stress users. 

Printed bike maps remain an important planning and encouragement tool and are likely the most comprehensive representations of a city’s bicycling network. The way bicycle planners and green lane advocates communicate our work and represent our networks will lay the groundwork for how we tell the story about where we are and where we are headed.

Coming next: Online representations of bicycling networks have the potential to push far beyond the limits of paper maps. How socially contagious real-time mapping, routing, evaluation, and research tools are changing the way we represent bicycling in cities.



Nathan Wilkes is a project engineer at the City of Austin, Public Works Department, Neighborhood Connectivity Division. He has worked on a variety of bicycle projects, including the recent Bluebonnet Street and Rio Grande Blvd green lanes in Austin.