Final Project Evaluation
The Traffic Calming Program (TCP) undertook a Streamlined Speed Bump Project in the Fall of 1995 to address traffic problems identified by residents along SW Kruse Ridge Drive from 62nd to Lesser.
The goal of the project was to enhance street safety and livability by reducing the 85th percentile speed of vehicles using SW Kruse Ridge Drive closer to the legal maximum speed limit of 25 miles per hour (mph). Speed bumps are the only device considered for streets like SW Kruse Ridge Drive, which are classified as Local Service Streets, are not transit or primary fire response routes and have vehicle volumes between 400 and 1700 vehicles per day. Speed bumps have proven to be effective tools to reduce vehicle speed without impacting access. It is not an intended goal to reduce traffic volume on low-volume Local Service Streets.
SW Kruse Ridge Drive serves a single family residence neighborhood. SW 62nd Avenue, to the west, is a Local Service street. Lesser Road, at SW Kruse Ridge Drive's east end, is a Neighborhood Collector street. SW Kruse Ridge Drive is fully improved with sidewalks and curbs. There is a slight horizontal curve and the street slopes down toward the west. A large portion of the daily traffic on SW Kruse Ridge Drive is believed to be cut-through traffic due to a northbound on/off ramp for I-5 just west of the neighborhood.
All residents along SW Kruse Ridge Drive were invited to an open house November 2, 1995 to review and comment on the proposed speed bump installation. Twelve households were represented at the open house. All of those who attended expressed approval for the proposed project. A petition was available at the open house for residents along SW Kruse Ridge Drive to sign and was circulated after the open house by a local resident. Of the 22 households along the street, 17, or 77.3%, signed the petition requesting speed bump installation.
Three 14-foot speed bumps, at 320 and 500 foot spacing, were constructed along the 0.23 mile stretch of SW Kruse Ridge Drive, 62nd to Lesser, June 2, 1996 by the Bureau of Maintenance.
As the graph shows, vehicle speeds, previously concentrated between 26 and 34 mph, have been shifted into the range of 20 to 25 mph. The 85th percentile vehicle speed before the project was 32.8 mph. After bump construction the average 85th percentile speed is 24.8 mph and ranges from a low of 22 mph (near the bumps) to a high of 26 mph.
Traffic volumes measured before bump construction were 540-950 vehicles per day (vpd). Higher volumes were measured at the west end. After bump construction volumes measured 480-900 vpd. Traffic volumes measured on side streets adjacent to SW Kruse Ridge Drive showed variable changes from volumes measured prior to speed bump construction. No side street volume measurements were so high as to require mitigation.
Traffic Calming on SW Kruse Ridge Drive, 62nd to Lesser has successfully reduced the 85th percentile closer to the posted speed and enhanced street safety and livability.