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Cycling -- Oregon -- Portland, Cycling -- Safety measures, Bicycles -- Oregon -- Portland -- Safety measures, Traffic safety, Sustainable development -- Oregon -- Portland


This research evaluates conflicts and delays caused by interactions between buses, bicycles, and right-turningvehicles. Two concerns caused by these overlapping bus, bicycle, and automobile facilities are analyzed; the firstconcern is the number of bus-bicycle conflicts (as a proxy for safety) and the second concern is bus delay. Video datawas collected and analyzed to quantify conflicts, travel time, and delay. For every bus passing through the study site,the mixed-traffic scenario that the bus incurs was categorized as one of 72 different combinations of bus, bicycle, andautomobile interactions. Video count data was weighted according to seasonal, weekly, and hourly bicycle volumedata to estimate the number of annual bus-bicycle conflicts. A regression analysis was performed to identify potentialsources of delays. The results indicate that each bicycle crossing the intersection after the bus (within 60 feet of thebus) contributes to bus delay. No statistically significant delay was found from the bicycles stopped in the bicycle box,bicycles stopped behind the bicycle box, bicycles that crossed the intersection before the bus, or the presence ofright-turning vehicles.


This is a final report, NITC-RR-1186, from the NITC program of TREC at Portland State University, and can be found online at:



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