Study Details
Study Title: Developing Crash Modification Factors for Separated Bicycle Lanes
Authors: Dixon et al.
Publication Date:FEB, 2023
Abstract: This project investigated how conversions of a traditional bicycle lane to a separated bicycle lane (SBL) influence the safety performance of the roadway. The study further assessed the role of the type of vertical element used in the SBL and its influence on safety performance based on a reduction in bicycle-related crashes. The study models included data from Cambridge, MA; San Francisco, CA; and Seattle, WA. Data from Austin, TX, and Denver, CO, were then used for model validation. The study produced exposure models and crash modification factors (CMFs) for Cambridge, San Francisco, and Seattle. The research summarizes the development of individual city models and a three-city composite model for CMFs. Assuming a baseline condition that uses a traditional bicycle lane and a countermeasure that upgrades the bicycle lane to an SBL, the resulting CMF values varied based on the type of vertical element. The resulting CMFs ranged from 0.28 to 0.60; however, the condition of converting a traditional bicycle lane to an SBL that uses flexible posts (known as flexi-posts) had a rounded CMF value of 0.50. This outcome suggests that this SBL treatment can reduce crashes by 50 percent. The report provides additional CMFs for variations of the bicycle lane and the vertical elements. These CMFs had similar results. The findings from this study can be useful to an agency interested in reducing bicycle-related crashes.
Study Citation: Dixon, K., R. Avelar-Moran, and M.M. Seyedeh. "Developing Crash Modification Factors for Separated Bicycle Lanes." Report No. FHWA-HRT-23-078. Federal Highway Administration. McVean, VA (2023).
Related Citations: Dixon, K., R. Avelar-Moran, and M.M. Seyedeh. "Developing Crash Modification Factors for Separated Bicycle Lanes." Tech Brief. Report No. FHWA-HRT-23-025. Federal Highway Administration. McVean, VA (February 2023).
Study Report: Download the Study Report Document
CMFs Associated With This Study
Category: Bicyclists
Countermeasure: Convert Blended vertical element Bike Lane to Flexible Delineator Post Bike Lane
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.605 | 39.5 |  | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Flush Buffered Bike Lane to Blended Bike Lane
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.729 | 27.1 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Flush Buffered Bike Lane to SBL with a blend of Flexi-post and other Vertical Elements
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.567 | 43.3 |  | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Flush Buffered Bike Lane to SBL with Flexi-posts
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.441 | 55.9 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Traditional Bike Lane to Blended Bike Lane
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.822 | 17.8 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Traditional Bike Lane to Flush Buffered Bike Lane
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 1.128 | -12.8 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Traditional Bike Lane to SBL with a blend of Flexi-post and other Vertical Elements
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.64 | 36 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Traditional Bike Lane to SBL with Flexi-posts
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.498 | 50.2 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Traditional or Flush Buffered Bike Lane to Blended Bike Lane
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.774 | 22.6 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Traditional or Flush Buffered Bike Lane to SBL with a blend of Flexi-post and other Vertical Elements
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.602 | 39.8 | | Vehicle/bicycle | Not specified | Urban |
Countermeasure: Convert Traditional or Flush Buffered Bike Lane to SBL with Flexi-posts
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.468 | 53.2 | | Vehicle/bicycle | Not specified | Urban |
