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Portland Bureau of Transportation

Phone: 503-823-5185

Fax: 503-823-7576

1120 SW Fifth Ave, Suite 800, Portland, OR 97204

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NW Mill Pond Rd - McDaniel to Engelman

Final Project Evaluation


The Traffic Calming Program (TCP) undertook a streamlined speed bump project in the summer of 1997 to address traffic problems identified by residents along NW Mill Pond Road from McDaniel to Engleman.
The goal of the project was to enhance street safety and livability by reducing the 85th percentile speed of vehicles using NW Mill Pond Rd closer to the legal maximum speed limit of 25 miles per hour (mph). Speed bumps are the only devices considered for streets like NW Mill Pond Rd, which are classified as Local Service Streets, are not transit or primary fire response routes and have vehicle volumes between 400 and 2000 vehicles per day. Speed bumps have proven to be 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.
NW Mill Pond Rd serves a single family residence neighborhood. NW McDaniel Rd, to the north, is a Local Service street. NW Engleman Street, at NW Mill Pond Rd's south end, is a Local Service street. NW Mill Pond Road has no sidewalks, but does have curbs.

Open House

Residents along NW Mill Pond Road were invited to an open house in February 4, 1998, to review and comment on the proposed speed bump installation. Twenty people attended the open house. Most of those who attended expressed approval for the proposed project. A petition was available at the open house for residents along NW Mill Pond Road to sign and was circulated after the open house by a local resident. Petition results were as follows:

Percent of Total
70.5 percent
0 percent
No Signature
29.5 percent
100 percent


Nine 14-foot speed bumps, at 400 to 450 foot spacing, were constructed along the 0.81 mile length of NW Mill Pond, from McDaniel to Engleman, on May 2, 1998, by the Bureau of Maintenance.

Vehicle Speeds

As the graph shows, vehicle speeds previously peaked ranged between 25 to 35 mph, now the peak range between 16 to 26 mph. The average 85th percentile vehicle speed before the project was 36 mph. Since bump construction the average 85th percentile speed is 26 mph. Before installation of the speed bumps 76 percent of drivers exceeded the posted speed limit of 25 mph and 15 percent exceeded the limit by 10 mph or more. Since bump construction 18 percent of drivers exceed the posted speed limit and 0.6 percent exceed the limit by 10 mph or more.

Traffic Volume

Traffic volumes measured before bump construction averaged 1056 vehicles per day (vpd). After bump construction volumes averaged 851 vpd.


Traffic Calming on NW Mill Pond, from McDaniel to Engleman has successfully reduced the average 85th percentile speed closer to the posted speed, enhancing street safety and livability.