A system was developed to control traffic congestion on the M25 motorway. Expert

A: So they’re looking at live action on the motorway?
D: Exactly. Because they’re working in real time and reacting immediately to the situation on the road, they hope to alleviate problems before they happen. So as the traffic gets heavier to the point where these waves of congestion are likely to form, the controllers monitoring the situation set speed limits at say, 50 or 60 mph to regulate the flow. Further back down the motorway at the back of the congestion zone, they set a lower speed limit, say 40 mph, which should theoretically help control the traffic through the problem area.
A: But traffic jams still happen on the M25, don’t they? I was in one a few months ago and we were at a standstill for ages.
D: Yes, of course, sometimes there are simply too many cars on the roads, I think what the programme said was that the ideal number of cars on the road is no more than 2,000 per lane per hour — something like that. Theoretically, this should keep traffic moving smoothly at all times. But of course the number of cars on the road far exceeds this — I think in some sections of the M25 there have been up to 200,000 vehicles a day.
A: Mmm. So, basically we need to reduce the number of cars on the roads. Well, that’s not likely to happen, is it?
D: No, but researchers are still looking into car technology that might help. As most congestion waves are caused by drivers braking too hard suddenly, the idea is that you install radar on the outside of the car and an onboard computer. The driver would activate the system when signs alerted him or her to a possible congestion zone. Then the computer would take over and then take control of the braking and acceleration. Because it can react much faster than a human driver, in theory, it would control the car smoothly through the zone.
A: A bit like an auto-pilot system?
D: Yes.