The Traffic Calming Program (TCP) undertook a streamlined speed bump project in the Spring of 1996 to address traffic problems identified by residents along SE 67th Avenue from Foster to Woodstock.
The goal of the project was to enhance street safety and livability by reducing the 85th percentile speed of vehicles using SE 67th Avenue closer to the legal maximum speed limit of 25 miles per hour (mph). Speed bumps are the only device considered for streets like SE 67th Avenue, 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.
SE 67th Avenue serves a primarily single family residence neighborhood. Foster, to the north, is a Major City Traffic street. Woodstock, at SE 67th Avenue's south end, is a Neighborhood Collector street. SE 67th Avenue has sidewalks and curbs. At three intersections SE 67th is stop controlled. A portion of the daily traffic on SE 67th Avenue is believed to be cut-through traffic due to a traffic signal at Foster.
All residents along SE 67th Avenue were invited to an open house June 10, 1996 to review and comment on the proposed speed bump installation. Eight households were represented at the open house. Those who attended expressed approval for the proposed project. A petition was available at the open house for residents along SE 67th Avenue to sign and was circulated after the open house by local residents. Of the 66 households along the street, 56, or 84.8%, signed the petition requesting speed bump installation.
Seven 14-foot speed bumps, at 370 to 670 foot spacing, were constructed along the 0.64 mile stretch of SE 67th Avenue, Foster to Woodstock, on August 18, 1996 by the Bureau of Maintenance.
As the graph shows, vehicle speeds, previously concentrated between 23 and 28 mph, have been shifted into the range of 20 to 25 mph. The average 85th percentile vehicle speed before the project was 30.5 mph north of Harold and 27.4 mph south of Harold. After bump construction the average 85th percentile speed is 24 and 25 mph, respectively, and ranges from a low of 20 mph (near the bumps) to a high of 26 mph.
Traffic volumes measured before bump construction were 880-1600 vehicles per day (vpd). After bump construction volumes measured 860-2100 vpd. Traffic volumes measured on side streets adjacent to SE 67th Avenue showed no significant increases from volumes measured prior to speed bump construction.
Traffic Calming on SE 67th Avenue, Foster to Woodstock has successfully reduced the 85th percentile closer to the posted speed and enhanced street safety and livability.