Portland State University. Department of Civil and Environmental Engineering
Date of Award
Master of Science (M.S.) in Civil & Environmental Engineering
Civil and Environmental Engineering
Traffic engineering, Traffic accidents -- Metropolitan areas -- Effect of vehicle speed on, Traffic flow -- Oregon -- Portland
Vehicle speed has long been one, if not the primary contributing factor to crashes, influencing both the probability and severity. Within the Portland metro area arterials have the highest serious crash rate per road mile and vehicle miles travelled. (Metro, 2012) The purpose of this research is to compile vehicle speeds along select arterial roadways within the Portland metro area and comparing it to applicable crash data. The roadway segment of SE Foster Road between SE 52nd avenues and SE 82nd avenues was selected, due to the simplicity of the physical as-built roadway properties along with available Bluetooth travel time data and Oregon Department of Transportation crash data.
The crash data is reported in one hour intervals, and the mean traffic speed was calculated to correlate to the crash data intervals. Crash types, causes, and severities were reviewed and compared vehicle speeds during the time of day and week. Negative correlating relationships between the crash types and vehicle speeds were determined, as most crashes occurred at speeds lower than the average mean. High traffic volume during peak travel times (3 PM to 6 PM) appears to be the primary contributing factor along the roadway segment. The second highest crash types are angle and turning maneuvers, both having a potential correlation to higher than average traffic speeds, but further review with detailed speed data at intersections would be required.
The roadway improvements currently proposed by the City of Portland, Bureau of Transportation aim to reduce the root causes for crashes along the corridor including implementation of a road diet; however, minor modifications to high risk intersections can be made to reduce severe crashes that are not currently identified in the plan.
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Vosper, Andrew C., "Impact of Speed on Vehicle Safety on Urban Arterial Roadways" (2017). Civil and Environmental Engineering Master's Project Reports. 34.