Monday, November 14, 2016

Speed enforcement causes accidents.

It's not the first time a study like this has been published, but this latest one (Strict speed enforcement detrimental to road safety, study finds) from the University of Western Australia has shown an interesting correlation between strict speed enforcement and road safety. Similar studies have found the same thing both in England and America - when you threaten drivers with automated cameras and roadside speed traps, they'll spend a lot more time concentrating on their speedometer, and a lot less time being aware of other hazards and situations outside the car.
By eliminating speed enforcement, or by raising the speed limit or increasing the overage tolerance, accident rates go down.
The same has been found to be true on motorways but the reasons are slightly different. The fact of life is that when speed limits are set artificially low, more drivers break those speed limits. The problem comes with the law-abiding drivers. For example when a speed limit on a motorway is set at 65mph but 95% of the drivers are doing 75-80mph, when they come across the law-abiding driver, the speed differential can be as much as 15mph. This reduces thinking time, increases closing speed and has the effect of causing either erratic braking or erratic maneuvering to get around the slower car.
When the speed limits are raised - for example to 75mph - the people who were doing 75-80 don't suddenly increase their top speed - they tend to keep driving at 75-80. But the law-abiding drivers are now doing 75mph which reduces the speed differential from 15mph to 5mph. This increases thinking time, and increases the time for slowing down and maneuvering, leading to a more calm traffic flow with less erratic behavior. The law-abiding drivers are no longer the 'rock in the river' that everyone is having to go around.
There's empirical evidence, studies and statistics to back this up too. It dates back 20 years in some cases (The Effects of Raising and Lowering the Speed Limit (US, 1996)
There are plenty of states in the US where even the police support the idea of raising speed limits (End of the Road for Speed Traps?)
For example, everywhere in the US where speed limits have been raised on the freeways, the accident rate has either remained the same or dropped. In comparison, on 'managed' motorways in England where speed-averaging cameras force drivers to drive at or below the limit, accident rates have increased in every instance.
Of course the first response many people will have is "just drive at the speed limit - you're breaking the law if you speed". Whilst that's technically true, we're not driving around in 1950's jalopies any more. Cars are perfectly safe at much higher speeds and the laws simply haven't kept up with the technology and capabilities of the vehicles.
The truth of the matter is that when you let politicians set arbitrary speed limits, they're going to be artificially low, and they're going to be out-of-date with modern motoring. It's long been proven that automated 'safety' cameras have no effect on accident rates, so with that simple fact in place, there can be only one reason for speed traps - revenue. Cities and police forces make millions in revenue from speeding motorists. But there is simply no justifiable reason ANY motorway should have a speed limit below 75mph. States in the US that still have 65mph limits - and the UK with it's 70mph limit - are just living in the past.
Telling people to drive at artificially low speed limits is outdated thinking that doesn't respect the current facts and studies. So when 95% of the traffic is going above the speed limit, and you're the law-abiding driver doing the speed limit, it might not be everyone else that is the problem .....


Paul Canciu said...

Very interesting topic; the studies you linked are very interesting as well. I mostly agree that speed limits that are unnecessarily low are for revenue purposes only. Some may have been forgotten, but the most are like that intentionally.

If I remember correctly, the speed limits in the US were set low during the oil crisis as an attempt to reduce consumption. After the oil crisis they remained low for no reason.

In Europe there is mostly a 100km/h (65mph) limit on single lane roads and 130km/h (80mph) on the "Autobahns". There are unrestricted sections in German Autobahns, but there are few drivers that actually drive over 140-150km/h even there.

In Romania there is a 10km/h leeway for speed tickets, so one could drive 109km/h in a 100km/h zone, but with a lack of motorways, a lot of people drive faster than that.

Vladimir said...

Top Gear made a nice test of the braking distance of a modern (high-end) car and the results are pretty impressive when compared to the requirement in the highway code :)

You can also take Germany as example, where the speed on most highways is not limited and the accidents are still much less than in the USA: