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Evaluation of bike boxes at signalized intersections.
Jennifer Dill1, Christopher M Monsere, Nathan McNeil
1Nohad A. Toulan School of Urban Studies and Planning, Portland State University, PO Box 751, Portland, OR 97201, United States. jdill@pdx.edu
Accident; Analysis and Prevention
|November 9, 2011
Summary
Bike boxes improve cyclist safety by reducing vehicle conflicts at intersections. Studies show increased compliance and fewer encroachments, with most road users finding them safer.
Area of Science:
- Urban planning
- Transportation engineering
- Traffic safety
Background:
- Bike boxes, also known as advanced stop lines, are traffic control devices designed to enhance cyclist visibility and reduce conflicts with motor vehicles.
- Right-hook incidents, where turning vehicles collide with cyclists, are a significant concern at signalized intersections.
Purpose of the Study:
- To evaluate the effectiveness of bike boxes in improving cyclist safety and traffic flow at signalized intersections.
- To assess user perceptions and compliance rates regarding bike box implementation.
Main Methods:
- A before-and-after observational study was conducted at 10 signalized intersections in Portland, Oregon.
- Video analysis was used to quantify vehicle and cyclist encroachment into bike boxes and crosswalks.
- Surveys were administered to cyclists and motorists to gauge their perceptions of safety and usability.
Main Results:
- A significant reduction in motor vehicle and bicycle encroachment into pedestrian crosswalks was observed at intersections with bike boxes.
- 73% of stopping vehicles did not encroach into the bike box, indicating high compliance.
- Observed conflicts decreased, and motorists' yielding behavior towards cyclists improved at bike box locations.
- Surveys indicated that both motorists and cyclists generally perceived bike boxes as enhancing intersection safety.
Conclusions:
- Bike boxes are an effective tool for reducing conflicts and improving safety for cyclists at signalized intersections.
- The study provides evidence for the positive impact of bike boxes on traffic safety, with high user acceptance.
- Further research is needed to definitively assess the impact of green coloring on bike box effectiveness.
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