Selective vehicle detection

Selective vehicle detection was the name of a bus priority system used by London Buses to allow traffic signals to selectively favour buses' movement through intersection by changing traffic light sequences and timings as buses approach. Following a successful large-scale trial in 1987, London Transport began introducing selective vehicle detection to shorten red lights or extend green lights in the 1990s.

Source: Wikipedia — Selective vehicle detection (CC BY-SA 4.0)