Monday, April 21, 2014

Faster really is safer.

From Auto Express recently:
MOTORING groups have backed a Danish report which claims that increasing speed limits is safer – but there are question marks over whether it could be easily implemented in the UK.
The study, carried out over two years by the Danish Road Directorate, looked at how driver behaviour and accident rates changed when speed limits were raised on single-carriageway rural roads and motorways.
One of the key findings was that after raising limits on two-way rural roads from 50mph to 56mph, accidents fell, due to a drop in the speed differential between the fastest and the slowest drivers, resulting in less overtaking. While the slowest drivers increased speeds, the fastest 15 per cent were found to be driving 1mph slower on average.
On sections of motorways where the limit was raised from 68mph to 80mph nine years ago, fatalities also fell.
A spokesman for the Alliance of British Drivers told Auto Express: "The research would seem to suggest that we are going the wrong way in the UK. This has proven that deaths and accidents have fallen despite limits increasing."
A Transport Research Laboratory (TRL) spokesman said the research raised interesting questions. "A key element isn't just the risk of the crash that is proportional to travelling speed for a given road, but the risk of injury should a collision occur." The Association of Chief Police Officers would not comment.

This isn't the first time a study like this has been published. There have been plenty of trials of increased speed limits where accident rates have fallen. The reason is simple : people are already driving quickly. Often quicker than the current limits dictate. Occasionally they'll come across people who are doing the limit - and it's that differential that causes the problem. The quicker person wants to get past - normally meaning an overtake. The more impatient they get, the more likely they'll do something silly, and the greater the liklihood of an accident. So what happens when the speed limit is raised? Those already travelling quicker will tend to stay at the same speeds they used to, whilst those who like to travel exactly at the limit will go quicker - to the new higher limit - thus reducing the differential in speed between them and everyone else.
I'm all for higher speed limits - the trend in the UK to keep slowing people down is clearly not working (see my post a few months back about how slower limits cause more accidents). And remember - the educated motorist understands that speed doesn't kill. It's the inappropriate use of speed that can amplify the end result of an accident.