Lane control is only legally allowed for something like 15 seconds,
Otherwise, with active cruise control a driver could get on the M40 and read the paper until he reached the M42. Active cruise is both a benefit and a burden. You could have set it to 70, then come up behind something doing 60, so the system slows you down. But if you then pull out to overtake there is a delay while the radar system readjusts, so you have to be prepared to override it with a stab of the accelerator if there is anything coming up on your right. This forces you to spend your time watching everything around and planning ahead, which isn't necessarily a bad thing. Jaguars, Mercedes, Infiniti and many other models offer ‘active’ radar controlled cruise control that slows the car down to the speed of the vehicle in front. Others have experimented with lane control. Citroen uses a warning system to jolt you awake if you stray off lane. But I think Honda was the first with a system to electronically keep the car in a lane.