The average duration of incidents assisted by the Northern Virginia (NOVA) Safety Service Patrol (SSP) was 17.3 percent shorter than the duration for matching incidents without NOVA SSP assistance.

Experience of a freeway SSP in Northern Virginia from 2003 to 2004.

Northern Virginia; Virginia; United States

Summary Information

In FY03 and FY04, budget cuts to the safety service patrol (SSP) in Northern Virginia (NOVA) diminished the SSP’s ability to respond to and clear incidents. Having experienced the strain of reduced resources, the NOVA SSP requested a formal Return on Investment (ROI) study of its services to demonstrate the benefits of SSP and thereby forestall additional plans for further budget reductions.


An evaluation of the NOVA SSP examined the duration of traffic incidents that had received assistance from NOVA SSP as well as similar incidents without SSP assistance on non-SSP routes (which had received assistance only from the Virginia State Police). The evaluation compared 22,233 SSP-assisted incidents that had occurred in the period from May 31, 2003 to June 1, 2004, to matching incidents on non-SSP roadways without SSP assist in the same time frame. Average incident durations were obtained by examining the incident "begin" and "end" times on incident records from the SSP and the Virginia State Police computer-aided-dispatch system.


The average duration of incidents with SSP-assist was 17.3 percent shorter than for those without SSP-assist (i.e., state police assist only).
  • For debris incidents, the average duration with SSP-assist was 25 percent shorter than for those without SSP-assist.
  • For breakdowns, the average duration with SSP-assist was 17.24 percent shorter than for those without SSP-assist.
  • For crashes, the average duration was 15.6 percent shorter than for crashes without SSP-assist.

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Assessing the Return on Investment of Freeway Safety Service Patrol Programs

Author: Dougald, L. E., & Demetsky, M. J.

Source Date: 2008



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Goal Areas


Related Metropolitan Integration Links

Link 13: Freeway Management to Incident Management

Typical Deployment Locations

Metropolitan Areas


freeway service patrol, courtesy patrols, highway helpers, freeway service patrols

Benefit ID: 2011-00679