fixed-time traffic lights
Refers to traffic signals that operate on a fixed schedule, as opposed to vehicle-actuated or adaptive signals. Used in traffic engineering contexts.
This intersection has fixed-time traffic lights, and the cycle becomes longer at night.
Vehicle-actuated traffic lights that respond to traffic demand, unlike fixed-time signals.
Compound of 時差 (time difference) + 式 (type) + 信号 (signal), literally 'time-difference-type signal'.