I've been spending quite a bit of the past week driving, and it got me thinking. Some of these thoughts have been developing for a while, through driving lessons and so on.
I guess my key thought is that a 2 second separation between cars isn't enough. That's not a reflection on my reaction time, but in terms of stress levels and also changing lanes, turning at junctions, etc.
I prefer to drive with a 5 or 10 second gap between me and the car in front. That gives enough room for people to pull in, or for the car in front to slow down and turn off without disrupting traffic flow much at all. The stop/start nature of driving in towns is largely because of people having to turn off. If we had bigger gaps between cars, it would be easier to turn through traffic and hence we wouldn't have to stop and start as much. I rather suspect many traffic lights would then become unneccessary.
Motorways also would benefit. If the distance between cars was increased to 10 seconds (for example), then accidents would be much less likely and it would be easier for lanes of traffic to merge. The resultant lane could have a temporarily reduced distance of 5 seconds, for example. It would also mean that the speed limit could be safely raised or even abolished.
I guess the difficulty would be that the capacity of the roads would therefore be decreased - some roads do usually have more than one car per 10 seconds per lane passing. Not many though, and it's usually only the roads where the number of turns has been greatly reduced to stop cars slowing to turn. Those roads could be kept at 2 second separation perhaps.
All just ideas, and there's probably a good reason they aren't being implemented. I just don't know what that reason is.