The safety service patrol (SSP) in Hampton Roads, Virginia, keeps travel lanes open for traffic by moving or helping to start stalled vehicles, removing debris from the roadway, and clearing traffic incidents. The Hampton Roads SSP assist motorists free of charge (to the drivers) by jump starting vehicles, providing gasoline, changing tires, etc. The SSP services approximately 80 miles on a 24-hour-per-day, 7-day-a-week basis. It patrols eight routes continuously and provides dispatch service on two routes. To justify funding the SSP, an evaluation was
The study compared the “begin” and “end” times of incidents on SSP routes to those on non-SSP routes (Virginia State Police (VSP) assist only). The study also used the Freeway Service Patrol Evaluation (FSPE) model to estimate incident-induced delay and associated delay savings attributable to SSP operations. The FSPE model employs deterministic queuing models to estimate motorist delay associated with queues that form during incident conditions. (Note that the results of the FSPE model did not account for day-to-day or seasonal variations. The study also did not attempt to estimate reductions in secondary incidents, or environmental or medical costs associated with SSP operations.)
Model parameters included:
- Freeway capacity values and remaining freeway capacity factors due to incidents from the Highway Capacity Manual 2000
- Emission rates from the Hampton Roads Planning District Commission (HRPDC)
- Clearance time reduction data from an analysis of the VSP CAD and Virginia's Archived Data Management System (ADMS) databases
- Travel time costs and fuel costs from the Texas Transportation Institute (TTI)
- Occupancy rates (persons/vehicle) from the Federal Highway Administration’s (FHWA) 2001 National Household Travel Survey
- The estimated total delay and fuel benefits per year were $11,075,893.
- The estimated savings in motorist delay per year were $455,856.
- The estimated fuel consumption savings per year were $687,624.
- The estimated emissions savings per year were 118,131 kg for reactive organic gases, 805 kg for carbon monoxide, and 12,115 kg for nitrogen oxides.
Annual Delay Savings (vehicle-hour)
Annual Fuel Consumption Savings (gal)
Annual Emissions Savings
Reactive Organic Gases (kg)
Carbon Monoxide (kg)
Nitrogen Oxides (kg)
|Naval Base/Reversible Roadway (I-64 and I-564)|
|Hampton Roads Bridge Tunnel|
|Coliseum A/Coliseum B|
|Monitor-Merrimack Memorial Bridge Tunnel|
|2 Outer/2 Inner (I-264)|