May 11, 2015
If you’d like to be able to ride a bike around your city without the stress of riding in high-speed traffic next to parked cars, you’re not alone. According to a survey of Portland, OR residents, 60% of residents are “interested but concerned” about riding a bicycle on city streets, while only 8% of residents felt “enthused and confident (7%)” or “strong and fearless (1%).” Those who are “interested but concerned” are understandably wary of riding a bicycle in traffic; bicyclists are vulnerable roadway users that are often relegated to an on-street bike lane alongside parked cars, if provided a bike lane at all. Cyclists often must ride in a travel lane, either taking the full lane as antsy motorists creep up behind them, or riding along the side of the lane as cars whip past them at 35 mph. Even if a user is subject to these conditions for only a small portion of their trip, it may discourage them from making that trip on a bicycle altogether.
While some roadways will never be bike-friendly, it is important to provide low-stress bicycle routes between residential neighborhoods, downtowns, and workplaces so that more people have the option of bicycling. A study by Mazza Mekuria of Evergreen Valley College, Peter Furth of Northeastern University, and Hilary Nixon of San Jose State University identifies four levels of traffic stress (LTS) for bicyclists, ranking from LTS 1 (suitable for children) to LTS 4 (suitable only for the “strong and fearless”). LTS 2 was identified as ideal for potential cyclists that are “interested but concerned”, as bicycle accommodations are physically separated from moving vehicles. If a robust network of LTS 1 or 2 roadways is provided in a city, more “interested but concerned” residents will choose to ride a bicycle, as many users would be able to travel to various locations on low stress roads. In the Netherlands, where 80% of the population rides a bicycle at least once per week, roadways are designed to be low-stress, with slow traffic speeds and/or separated bicycle accommodations, typically achieving LTS 2.
In the Boston area, there are few roadways that are LTS 1 or 2, aside from quiet neighborhood streets. Most trips require bicycling along at least one particularly stressful roadway. Staniford Street and Causeway Street in Boston consist of four travel lanes (more in some locations), parallel parking, and no bicycle accommodations, qualifying them as LTS 3 or 4. Commercial Street to the east is a three-lane roadway with bicycle lanes alongside parked vehicles, and likely qualifies as LTS 3. As part of the Connect Historic Boston project, which will begin construction in Spring 2015, Howard Stein Hudson designed a 1.5-mile cycle track on Staniford, Causeway, and Commercial streets, which will separate bicyclists from vehicle traffic and provide dedicated crossings at intersections, improving these roadways to LTS 2. This will allow novice bicyclists to ride through the West End and North End with minimal stress. Similarly, protected bike lanes and protected intersections are proposed on Commonwealth Avenue, currently an LTS 3 roadway. If built, these protected bike lanes would improve a large segment of Commonwealth Avenue, a major commercial roadway that is home to Boston University, to LTS 2
A low-stress route may be interrupted by one high-stress area, which may discourage bicyclists from using that route at all. For example, the Minuteman Commuter Bikeway is a 10-mile rail trail between Bedford and Cambridge that is completely separated from vehicle traffic and typically has low-stress, mid-block intersections on relatively low-volume roadways. It is an LTS 1 facility along most of its length; however, there is a major barrier at Arlington Center that may discourage some users from using the bikeway. Bicyclists are asked to dismount and walk their bikes through the busy intersection of Massachusetts Avenue/Mystic Street (Route 3A) before continuing. Howard Stein Hudson designed a solution for this intersection that will give users the option to remain on their bikes, providing a markedly lower-stress connection between the two legs of the Minuteman Bikeway.
Would lower traffic stress compel you to ride a bike more often? What high-stress locations along your ride interrupt an otherwise low-stress trip?
Mekuria, Furth, Nixon study: http://transweb.sjsu.edu/PDFs/research/1005-low-stress-bicycling-network-connectivity.pdf
Level of Traffic Stress Rubric
|Level of Traffic Stress|
|LTS 1||Presenting little traffic stress and demanding little attention from cyclists, and attractive enough for a relaxing bike ride. Suitable for almost all cyclists, including children trained to safely cross intersections. On links, cyclists are either physically separated from traffic, or are in an exclusive bicycling zone next to a slow traffic stream with no more than one lane per direction, or are on a shared road where they interact with only occasional motor vehicles (as opposed to a stream of traffic) with low speed differential. Where cyclists ride alongside a parking lane, they have ample operating space outside the zone into which car doors are opened. Intersections are easy to approach and cross.|
|LTS 2||Presenting little traffic stress and therefore suitable to most adult cyclists but demanding more attention than what might be expected from children. On links, cyclists are either physically separated from traffic, or are in an exclusive bicycling zone next to a well-confined traffic stream with adequate clearance from a parking lane, or are on a shared road where they interact with only occasional motor vehicles (as opposed to a stream of traffic) with a low speed differential. Where a bike lane lies between a through lane and a right-turn lane, it is configured to give cyclists unambiguous priority where cars cross the bike lane and to keep car speed in the right-turn lane comparable to bicycling speeds. Crossings are not difficult for most adults.|
|LTS 3||>More traffic stress than LTS 2, yet markedly less than the stress of intergrating with multilane traffic, and therefore welcome to many people currently riding bikes in American cities. Offering cyclists either an exclusive riding zone (lane) next to moderate-speed traffic or shared lanes on strees that are not multilane and have moderately low speed. Crossings may be longer or access higher-speed roads than allowed by LTS 2, but are considered acceptably safe to most adult pedestrians.|
|LTS 4||A level of stress beyond LTS 3.|
Source: Mekuria, Furth, and Nixon. “Low Stress Bicycling and Network Connectivity.” Mineta Transportation Institute Report 11-19, May 2012. Page 14. Accessed electronically.