TTI’s Dadashova Leads Safety Evaluation of On-Street Bicycle Facility Designs

Texas A&M Transportation Institute (TTI) Assistant Research Scientist Bahar Dadashova is the team lead on a recently contracted project evaluating the safety of on-street bicycle facility design features. Funded primarily by the National Cooperative Highway Research Program, the effort also includes support from Portland State University, Toole Design Group and Safe Streets Research and Consulting.

The Problem

There are over 600 bicyclist fatalities reported annually in the United States and that number continues to grow. And that statistic doesn’t include the thousands of bicyclist-related injuries that occur on the road.

“Whenever you analyze bicyclist crash data, it’s difficult to get an exact readout on how many occur annually,” says Dadashova. “Not all crashes that occur are reported to the authorities, so those data are lost.”

To improve and expand bicyclist networks, many state and local departments of transportation (DOTs) have installed both non-separated and separated on-street bicycle facilities (i.e., bicycle travel lanes) to address safety concerns and promote bicycling.

The differences between the two? Non-separated on-street bicycle facilities are marked off from vehicle traffic (e.g., by a painted buffer or striping). Separated on-street bicycle facilities are divided from vehicle lanes both horizontally and vertically by flexible delineators, curbs, parking lanes or other barriers.

The Project

To adequately assess and implement effective measures aimed at reducing bicyclist-related injuries and fatalities, state DOTs and other transportation agencies need detailed information on potential safety improvements for a range of sites. Dadashova’s project seeks to provide data-driven guidelines for selecting appropriate design features that enhance both existing and new cycling facilities. The guidelines will be based on:

• a qualitative analysis of crash patterns as well as an evaluation of roadway characteristics,
• land use patterns, and
• human factors that increase conflicts and the risk and severity of midblock (i.e., non-intersection) crashes involving bicyclists.

“Once completed, our guidelines will help transportation practitioners make informed decisions when deciding between non-separated and separated facilities,” Dadashova notes. “And, by extension, we’re hopeful our research will go a long way in preventing injuries and saving lives.”