Signal Preemption System
Intersections at the base of a steep and/or long grade create a potentially dangerous situation. A large truck that loses control on the descent of the grade may enter the intersection at high speed. Vehicles and pedestrians within the intersection may be struck by the truck with the possibility of property damage, injury or even loss of life resulting.
The IRD signal preemption system uses WIM technology to detect runaway trucks on a steep grade which leads into a signalized intersection. If a runaway situation is detected, the signal controller is triggered to provide a green light as the vehicle approaches the intersection. The preemption system will provide the opportunity for vehicles and pedestrians to clear the intersection and avoid potentially catastrophic accidents.

- Truck Safety Advisory Systems (pdf - 275 kb)
(PDF files require Adobe Reader)
