Final Project Evaluation
The Traffic Calming Program (TCP) undertook a speed bump project in the Fall of 1995 to address traffic problems identified on SW Fairview Boulevard between Skyline Blvd. and Kingston Drive as part of the Westside Corridor Traffic Management Plan.
The goal of the project was to mitigate high speeds of drivers using Fairview Boulevard as an alternative to principal routes. Speed bumps enhance street safety and livability by reducing the 85th percentile speed of vehicles using SW Fairview closer to the legal maximum speed limit of 25 miles per hour (mph). Speed bumps have proven to be effective tools to reduce vehicle speed without impacting access, though volume reductions are typical.
SW Fairview Boulevard, a Neighborhood Collector, serves as access to several single family residence neighborhoods in a rural urban setting. Skyline Blvd., to the West, and Kingston Drive, to the East, are Neighborhood Collectors. SW Fairview Boulevard between Skyline Blvd. and Kingston Drive has neither curbs or sidewalks and has several horizontal curves limiting sight distance. Additionally, a majority of the street is on steep grades confining the project to the west end. A significant portion of the daily traffic on SW Fairview Boulevard is believed to be cut-through traffic due to congestion caused by light rail construction on Highway 26.
Five 22-foot speed bumps, at 340 to 800 foot spacing, were constructed along the west 0.51 mile stretch of SW Fairview in October of 1995 by the Bureau of Maintenance.
As the graph shows, vehicle speeds, previously concentrated between 32 and 40 mph, have been shifted into the range of 26 to 31 mph. The average 85th percentile vehicle speed before the project was 36.8 mph. After bump construction the average 85th percentile speed was 30.7 mph and ranged from a low of 27 mph (near the bumps) to a high of 34 mph.
Traffic volumes measured before bump construction were 1500-1620 vehicles per day (vpd). After bump construction volumes measured 1100-1400 vpd.
Traffic Calming on SW Fairview has successfully reduced the 85th percentile closer to the posted speed and enhanced street safety and livability.