Generally speaking, street lights are useless after midnight, so the usual practice is to turn off the lights or turn on half the brightness after 12 o'clock. But the most reasonable way is to control the brightness of the street lights according to the traffic flow, or even control the brightness completely adaptively.
In order to realize this kind of intelligent dimming, it is actually very simple. As long as the curve of traffic flow statistics in this area is input to a single chip microcomputer, the PWM dimming signal is given to the constant current drive source according to this curve.