San José made its buses 20 per cent faster by changing the lights
AI-driven signal priority now runs on 24 bus routes. A two-route pilot halved the time buses spent waiting at red lights.
San José, California, has increased bus speeds by 20 per cent on 24 routes across the city by using AI to give buses priority at traffic signals.
How it works
A transponder on each bus communicates with the traffic signals. The system, from the traffic software company Lyt, uses real-time data to predict when a bus will reach an intersection and adjusts the signals to keep it moving.
The city began testing signal priority on two routes in 2023. That pilot cut the time buses spent waiting at red lights by 50 per cent and helped more of them stay on schedule, which led to the citywide rollout announced in February.
Cheap speed
Faster buses usually mean dedicated lanes, which are expensive and politically hard. Signal priority uses equipment the city already owns and changes only when the lights turn green. It will not match a bus lane in heavy traffic, but as a first step it gives riders a measurably quicker trip at modest cost.
Research desk, Online
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