Final Project Evaluation
The Traffic Calming Program (TCP) undertook a streamlined speed bump project in the Summer of 1996 to address traffic problems identified by residents along NE Fargo from 103rd Avenue to 111th Drive.
The goal of the project was to enhance street safety by reducing the 85th percentile speed of vehicles using NE Fargo closer to the legal maximum speed limit of 25 miles per hour (mph). Speed bumps are the only devices considered for streets like NE Fargo, 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 are effective tools to reduce vehicle speed without affecting access. It is not an intended goal to reduce traffic volume on low-volume Local Service Streets.
NE Fargo, 103rd Avenue to 111th Drive, serves a primarily single family residence neighborhood. NE 103rd, to the west, is a Local Service street. 111th Drive, at NE Fargo's east end, is a Neighborhood Collector street. NE Fargo has neither sidewalks nor curbs. There is a vertical curve at the west end which limits sight distances. A large portion of the daily traffic on NE Fargo is believed to be cut-through traffic due to a freeway off-ramp at 103rd.
All residents along NE Fargo, 103rd Avenue to 111th Drive, were invited to an open house September 9, 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. There was concern expressed about the possibility of drivers going around the bumps due to the lack of curbs. A petition was available at the open house for residents along NE Fargo to sign and was circulated after the open house by local residents. Of the 65 households along the street, 46, or 70.8%, signed the petition requesting speed bump installation.
Four 14-foot speed bumps, at 420 to 540 foot spacing, were constructed along the 0.42 mile stretch of NE Fargo, 103rd Avenue to 111th Drive, May 17, 1997 by the Bureau of Maintenance.
As the graph shows, vehicle speeds, previously concentrated between 26 and 31 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 27 mph and ranges from a low of 24 mph (near the bumps) to a high of 29 mph. Before installation of the speed bumps 69% of drivers exceeded the posted speed limit of 25 mph and 8.7% exceeded the limit by 10 mph or more. Since bump construction 24.9% of drivers exceed the posted speed limit and 1% exceed the limit by 10 mph or more.
Traffic volumes measured before bump construction averaged 830 vehicles per day (vpd). After bump construction volumes average 720 vpd. Traffic volumes measured on side streets adjacent to NE Fargo showed no significant increases from volumes before speed bump construction.
Traffic Calming on NE Fargo, 103rd Avenue to 111th Drive has successfully reduced the 85th percentile closer to the posted speed and enhanced street safety and livability.