Evaluation of Bike Boxes at Signalized Intersections
This report presents a before-after study of bike boxes at 10 signalized intersections in Portland, Oregon. The bike boxes, also known as advanced stop lines or advanced stop boxes, were installed to increase visibility of cyclists and reduce conflicts between motor vehicle and cyclists, particularly in potential "right-hook" situations. Before and after videos were analyzed for seven intersections with green bike boxes, three intersections with uncolored bike boxes, and two control intersections. User perceptions were measured through surveys of cyclists passing through five of the bike box intersections and of motorists working downtown, where the boxes were concentrated. Both the observations and survey of motorists found a high rate of compliance and understanding of the markings. Overall, 73% of the stopping motor vehicles did not encroach at all into the bike box. Both motor vehicle and bicycle encroachment in the pedestrian crosswalk fell significantly at the bike box locations compared to the control intersections. The bike boxes had mixed effects on the motorists’ encroachment in the bicycle lane. The number of observed conflicts at the bike box locations decreased, while the total number of cyclists and motor vehicles turning right increased. Negative-binomial models based upon the data predict fewer conflicts with the boxes, particularly as right-turning motor vehicle volumes increase. Observations of yielding behavior at two bike box and one control intersection found an improvement in motorists yielding to cyclists at the bike box locations. Differences in the traffic volumes and location contexts make firm conclusions about the effects of green coloring of the boxes difficult. Higher shares of surveyed motorists felt that the bike boxes made driving safer rather than more dangerous, even when the sample was narrowed to respondents who were not also cyclists. Over three-quarters of the surveyed cyclists thought that the boxes made the intersection safer.
- Record URL:
- Summary URL:
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Supplemental Notes:
- This document is disseminated under the sponsorship of the U.S. Department of Transportation University Transportation Centers Program and the City of Portland in the interest of information exchange.
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Corporate Authors:
City of Portland
Office of Transportation
1221 SW 4th Avenue, Room 110
Portland, OR United States 97204Oregon Transportation Research and Education Consortium
P.O. Box 751
301A Engineering Building
Portland, OR United States 97207Research and Innovative Technology Administration
1200 New Jersey Avenue, SE
Washington, DC United States 20590 -
Authors:
- Dill, Jennifer
- Monsere, Christopher
- McNeil, Nathan
- 0000-0002-0490-9794
- Publication Date: 2011-1
Language
- English
Media Info
- Media Type: Web
- Edition: Final Report
- Features: Appendices; Figures; Photos; References; Tables;
- Pagination: 126p
Subject/Index Terms
- TRT Terms: Before and after studies; Highway safety; Road markings; Signalized intersections
- Candidate Terms: Bicycle boxes (Intersection element)
- Uncontrolled Terms: Bicycle safety
- Geographic Terms: Portland (Oregon)
- Subject Areas: Pedestrians and Bicyclists; Safety and Human Factors; I85: Safety Devices used in Transport Infrastructure;
Filing Info
- Accession Number: 01337270
- Record Type: Publication
- Report/Paper Numbers: OTREC-RR-11-06
- Files: UTC, TRIS, USDOT
- Created Date: Apr 19 2011 7:17AM