Most of us will have been taught the two-second rule when learning to drive.
The two-second rule is a rule of thumb by which a driver may maintain a safe following distance at any speed. The rule is that a driver should ideally stay at least two seconds behind any vehicle that is directly in front of the driver's vehicle.
But what research is there to lend weight to this rule of thumb?
I always liked to think that giving a 2 second gap between you and the vehicle in front was clearly a sensible idea.
Unfortunately, increasingly on British roads I see people driving just a few meters behind the vehicle in front. At 70 miles per hour, 3m puts you just one tenth of a second behind that vehicle. To put that into context, the Stanford press release Sleep deprivation shown to have as much impact on reaction time as alcohol, talks about reaction times in excess of 2 tenths of a second (200ms) for Navy Fighter Pilots, while the wikipedia mental chronometry page suggests a mean reaction time to a visual stimulus of around 190ms for college-age individuals.
Have there been studies looking at the relationship between following distance and accident rates? Between following distance and accident severity? What about between following distance and the number of accidents that would have been near misses if the following distance had been greater?
I have had a look, but it's not my field so don't have much of a clue as to where to start looking for such data or which journals would publish such studies.