A toolkit to measure and value “community severance” due to traffic

By Erin Evenhouse

A high-traffic road can divide a community in more ways than one. Researchers haven’t always been able to show to what extent such roads can harm a community’s access, health, or quality of life. A new study outlined in the latest volume of the Journal of Transport and Health looked at one corridor to examine just that.

The Street Mobility Project Toolkit was developed by University College of London (UCL) to help communities measure how a busy road negatively impacts them. This phenomenon is termed “community severance.” The article describes what a team of researchers found when they applied every tool in this toolkit to a section of Finchley Road, a busy London arterial.

The study finds that heavily-trafficked roads have numerous negative health and social impacts on nearby community members. While Finchley road is a bustling commercial corridor for drivers and pedestrians alike, the fact that people can walk alongside it does not negate extensive measurable externalities for community members on both sides.

English researchers will continue applying the toolkit to better understand community severance. In addition to London’s Finchley road, they have validated findings with divided populations in Birmingham— total population ~1.1M—and Southend-on-Sea—total population ~180K. Their goal is to develop statistically significant findings across all of the corridors studied.

While English researchers continue studying the toolkit as a whole, its various tools could already be useful for American transportation professionals. Qualitative and quantitative findings in the study support the validity of the individual tools in UCL’s toolkit. Researchers employed methodical triangulation of findings in order to validate their methods.

UCL table

UCL’s Street Mobility Project Toolkit was designed to capture a variety of ways that busy roads can hinder community access to goods and services or diminish community health and quality of life. Information reflects Table 1 of the Street Mobility Project Introduction.

UCL designed the toolkit so the public and community leaders could select tools according to their own ability to gather and analyze the data. From a research perspective, a community may only capture its full “severance” by employing all of the tools, but doing that may not always be necessary for community-based planning and mitigation.

Transportation and community leaders can employ these tools to put data behind a desired transportation improvement, like a new crosswalk or traffic calming strategy. This study validates the tools above as sound methods for gathering that data and, as the study authors put it, “by providing valuations of the impacts of community severance on the local community, policy-makers and practitioners can prepare business cases for expenditure to reduce severance.”

Accessibility—how easily people can reach destinations by different modes—is a growing measure for evaluating transportation performance. Emerging state-of-practice tools evaluate destination access by travel time, as presented in SSTI webinars in March and April. These tools can be combined with other metrics to inform transportation decision making at the project or program level.

As methods of measuring destination access—or barriers to that access—continue to evolve, they will become increasingly integral to how transportation decisions are made. As this study validates, community partners can play an important role in data-driven decision making.

Erin Evenhouse is a Program Associate for SSTI.