Today’s invention is an improvement on this one.
When a road accident occurs, there is almost always a loud bang.
Streetlights could be fitted with microphones to detect this, so that when there was a loud impact, the nearest few lights would flash on and off, indicating a problem to oncoming drivers.
The flickering of lights on either side of the bang could be timed so as to apparently point to the lamp nearest the accident (as cone lights currently do with eg roadworks).
The lights might also send a message to the police or at least take a photograph of the vicinity (when the lights were in the ‘on’ state).
A more advanced version would have the streetlight flashing be radio-triggered by eg airbag or bumper sensors within vehicles themselves.