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SPD deploys photo speed van on arterials

Speed Van Photo Enforcement


During the 2008-2009 school year, the Seattle Police Department Traffic Section deployed a mobile van equipped with traffic safety camera and across-the-road radar to document and issue citations for school zone speed violations.  The principal purpose of this pilot project, which was conducted pursuant to provisions of the Revised Code of Washington and local ordinance, was to enhance pedestrian safety by slowing vehicular speeds and citing violators proceeding in excess of the posted 20 MPH limit in school zones when children are present. 

Preliminary results of this work suggest that the project has succeeded in this broad purpose.  Following is a thumbnail recap of the project.

The research design called for mapping vehicle speeds at the beginning and end of speed van operations.  Focused speed enforcement operations were conducted at two different kinds of elementary schools in all parts of the city:  1) schools with electronic beacons set to flash when children are coming to and departing from school; and 2) schools without beacons.  These schools are identified below:

With Beacons Without Beacons
Bagley Catherine Blaine
Bryant/Assumption Schmitz Park
Gatewood Stevens
West Woodland  

In addition, three schools were monitored as “control sites” for sake of comparison with the test schools:  Alki, Beacon Hill, and Pathfinder.

Prior to issuing citations, the specially equipped mobile speed van captured 413 speed violations during a five-week warning period.  Officers began issuing $189 citations on the 13th of October, 2008 and continued through the end of the school year in June 2009.  During that time, the speed van deployed to the test schools a total of 59 times and 831 citations were issued.

Baseline speeds at the test schools were recorded at the outset of the 2009 school year, after three months without van operations.  Comparing these baseline speeds with the results achieved during the preceding school year show, in every case, that the speed van lowered both average and 85 percentile speeds, typically by 5 to 10 MPH – a significant difference in the world of pedestrian-vehicle collisions. 

Typical baseline speeds at these schools, in the absence of the speed van, averaged from 23 to 29 MPH, with 85th percentile speeds ranging from 25 to 34 MPH.  In comparison, during deployment of the van the average speed of vehicles was clocked at 18.3 MPH, with the 85th percentile speed of 22.4 MPH.  Both of these speeds show enhanced compliance with the 20 MPH posted limit on the part of the typical driver.
At beacon schools, which furnished the best test of the effects of automated enforcement, the van worked each school for an extended period, typically for two to three weeks.  The average violator was clocked at 30.7 MPH in the 20 MPH zone.  As additional evidence of the effect of the van in reducing excessive speeds, the percentage of vehicles cited for speeding declined at each of the four beacon schools, typically by 50%, from early to late in the deployment cycle.

No such pattern was observed at the small number of “control schools,” where speed studies were conducted at the beginning and close of the school year.  Average speeds at two of the three control schools actually increased between the beginning and end of the school year.

Use of photo radar in school zones continues during the 2009-2010 school year.


Beginning in April 2010, SPD will initiate photo speed enforcement on arterial streets in a pilot project authorized during the 2009 state legislative session.  Using the same photo radar van employed in school zones, the SPD Traffic Section will deploy the van to selected arterial locations four days per week, in an effort to gauge effects on speeding. 

Operations will begin during the week of April 19, 2010 with a three-week warning phase, followed by issuance of citations for speeding on May 10.  The fine associated with these citations will vary between $124 and $247 depending on the extent to which the vehicle exceeds the posted speed.

Arterial speed enforcement operations for the pilot project will focus initially along two busy streets that have experienced problems with speeding and vehicle accidents:

  • Elliott Avenue West
  • 35th Avenue Southwest

Depending on experience with these locations, other sites may be chosen for arterial speed operations before the pilot concludes in late fall 2010.

The future of the arterial speed pilot will be determined by the State Legislature and Governor after they receive a report on project results from Seattle and Tacoma early in 2011.  The final pilot project evaluation report will be prepared and submitted to the Legislature by the Washington Traffic Safety Commission.  For more infomation on this program, visit our website at