instead of having speed cameras set up to catch people “speeding” there should be cameras on the motorways to catch people not using safe distances, as cars driving too close to each other is more dangerous than going faster than 70mph (too fast is still a problem, and 70 mph is only too fast if you are too close)
So what I propose is to have a strip of motorway with cameras every mile or so that count up to 4 seconds with a display that the drivers can see (maybe 4 bars). if you pass the camera under the 4th bar then you will get a fine.
When a driver passes the camera the display for the car behind is reset to 0 and it counts up.
The main benefit is that this will work as traffic shaping in all traffic conditions, it will work at night when goin 120mph (warning of a previous driver infront of them) or at 20 mph in highly congested traffic (forcing smoother driving, and less stop and go)