Signal pre-emption detects when a late bus is approaching a signalised intersection and manages the traffic lights appropriately. The system consists of detectors in the roads, which are linked to traffic lights. When a bus passes over a detector in the road, a message is sent ahead that a bus is on its way. If the lights are about to turn red they are instructed to stay green until the bus passes through. If the lights are already red, then the green phase is brought forward.
Advantages of signal pre-emption
- Reduce corridor time for buses
- Used in conjunction with bus lanes will increase traffic flow
- Reduce buses running behind schedule due to traffic congestion