Measuring Bicycle Network Connectivity and Comfort
Originally developed by researchers at the Mineta Transportation Institute, Bicycle Level of Traffic Stress (LTS) quickly assumed the mantle of industry best practice for assessing the comfort and connectivity of bicycle networks. Increasingly, state governments, non-profits, and other organizations are looking for ways to adapt the Mineta Transportation Institute’s framework to their local conditions and available data. And, while there is no one “right” way to conduct an LTS analysis, understanding its indispensable components can help you develop an analysis that best fits the context of your city, county, or region.
What is LTS ?
LTS promises an objective, data-driven approach to evaluating bikeways by matching up roadway design, traffic volumes, and motor vehicle speeds to individual perceptions of bicyclist comfort and a willingness to travel out of ones’ way to maintain that level of comfort.
Like all similar analyses, LTS is subject to the availability and thoroughness of travelway data. Common inputs include posted or observed speed limit, presence and width of bikeways, intersection control, proximity to motor vehicle parking, blockage of the bikeway by motor vehicles, traffic volumes and truck route designation, and gaps in the bikeway network.
While it is unlikely that your jurisdiction collects all these potential inputs, for the data that is available, a careful cleaning and vetting process may be necessary. This may involve using aerial imagery for verification or hopping on a bicycle and riding around the network with a group of residents from various backgrounds to balance the hard numbers with diverse perspectives.
Why Does LTS Matter?
To help identify what data may be most appropriate for your local context, it may be helpful to consider what type of bikeway network that residents and visitors to your city, county, or region may want or what threshold must be crossed to convince non-bicyclist to give bicycling a try.
Studies suggest that traffic stress, caused by perceived safety issues (J. Pucher, C. Komanoff, and P. Schimek, “Bicycling renaissance in North America? Recent trends and alternative policies to promote bicycling,” Transp. Res. Part Policy Pract., vol. 33, no. 7/8, pp.625–654, 1999.), extended travel distances (J. Hood, E. Sall, and B. Charlton, “A GPS-based bicycle route choice model for San Francisco, California,” Transp. Lett. Int. J. Transp. Res., vol. 3, no. 1, pp. 63–75, Jan. 2011.), and difficult terrain (F. Godefroy and C. Morency, “Estimating Latent Cycling Trips in Montreal, Canada,” Transp. Res. Rec. J. Transp. Res. Board, vol. 2314, no. -1, pp. 120–128, Dec. 2012), are a few of the greatest deterrents to bicycling.
Creating a less stressful bicycle network though minimizing or eliminating some of these factors can help to make bicycling more appealing to a broader segment of the population. Ultimately, LTS tries to capture the increasing number and diversity of people that may be willing to use a bicycle facility as these stress factors are reduced.
A continuous low-stress network is essential for bicyclists of all ages and abilities to travel easily throughout the network.
LTS scoring is designed to correspond with the “Four Types of Bicyclists” categories, with a range of LTS 1 to LTS 4 representing a spectrum from lowest stress to highest stress facilities. Corridors and intersections are classiﬁed into one of four LTS scores — LTS 1, LTS 2, LTS 3, and LTS 4, where 1 represents the lowest stress, and 4 represents highest stress and discomfort. At its core, as motor vehicle traffic volumes increase and the separation between a person bicycling and motor vehicle traffic decreases, the LTS scores show an increase in level of stress. The level of traffic stress scores are mapped to illustrate the low stress connections and gaps throughout a given community.
The most desirable bicycling score, LTS 1, is assigned to roads that would be suitable for most children to ride or suitable for inexperienced adults riding bicycles or families with small children. LTS 1 also applies to multi-use paths that are separated from motorized traffic. LTS 2 are roads that could be comfortably ridden by the general adult population.
The higher levels of traffic stress, LTS 3 and LTS 4, correspond to types of cyclists characterized by Portland’s bicycle coordinator Roger Geller in his Four Types of Cyclists report, a categorization of cyclist types which is commonly accepted throughout the bicycle planning field in the US. The Four Types of Cyclists typologies help us identify which segments of the population need lower stress facilities to try bicycling or to bicycle more often.
LTS 3 is assigned to roads that would be acceptable for bicycle travel by “enthusiastic and conﬁdent” bicyclists, and LTS 4 represents roads that are only acceptable to “strong and fearless” bicyclists who better tolerate roadways with higher motorized traffic volumes and speeds.
LTS results demonstrate the importance of assessing a bikeway networks not only for connectivity but also for their ability to serve the diverse needs of all its users. To serve all types of people riding bicycles, a bikeway network should consist of continuous low-stress LTS 1 and LTS 2 segments and intersections. By prioritizing the locations that likely dissuade people from riding bicycles, the LTS analysis helps focus on identifying the improvements that will bring the high-stress LTS 3 and LTS 4 gaps down to low stress LTS 1 and LTS 2 levels, thereby removing the barriers to bicycling for a large proportion of the population.
While the LTS analysis focuses on bicycle travel, improvements for bicyclists generally translate into improved conditions for pedestrians, as well. This is particularly true for crossing conditions, as improvements are measured in terms of reduced exposure to motor vehicle travel speed and the number of travel lanes crossed.
Once the LTS for an existing facility is identified and a city, county, or region has determined which type(s) of bicyclists it would like to encourage to use the facility, the next step is to identify what type of bikeway will meet their needs.
High-quality, connected networks are comfortable for majority of people and not just for experienced bicyclists; they attract a diversity of users, make bicycling a viable, inclusive, and safe mode for everyday transportation, and have the most impact on congestion.