Conventional or parking-protected bike lanes? A Full-Bayesian before-and-after assessment

Abstract

Objective

Biking infrastructure plays a crucial role in ensuring cyclists’ safety and encouraging more people to bike. Recently, many North American municipalities started to adopt a new bike lane design, namely the parking-protected bike lane (PPBL), in which the bike lane is placed between the sidewalk and the parking lane. This study aims to assess the safety impacts associated with converting conventional bike lanes (CBLs) to PPBLs.

Methods

To that end, collision and traffic data were collected at 19 street sections from three corridors in Vancouver and Ottawa before and after the conversion. Poisson-Lognormal Linear Intervention model was developed to undertake a Full Bayesian before-and-after analysis to evaluate the change in the frequency of bike-vehicle collisions and other collaterally affected collisions (i.e., total and rear-end collisions) after implementing PPBLs.

Results

Reductions of 31.2%, 16.5%, and 4.4% were observed for total, rear-end, and bike collisions, respectively, after implementing the PPBLs, but the results varied significantly depending on the corridor characteristics.

Conclusion

Overall, PPBLs demonstrated positive impacts on cyclist safety in some corridors, but their performance is highly sensitive to bike path opening density, intersection density, and intersection treatments.

Keywords:

• Cyclist safety
• bike infrastructure
• parking-protected bike lanes
• before-and-after evaluation
• Full-Bayesian analysis

Disclosure statement

The authors report there are no competing interests to declare.

Data availability statement

The data that support the findings of this study are openly available in Open Ottawa at https://open.ottawa.ca/search?q=collision and in Tableau Public at https://public.tableau.com/app/profile/icbc/viz/ICBCReportedCrashes/ICBCReportedCrashes. Raw data for collisions before treatment at Vancouver sites were generated at Insurance Corporation of British Columbia. Derived data supporting the findings of this study are available from the corresponding author Y.I.M. on request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.