12.6.2012 Do we want an 80 mph speed limit?

Since the early days of the motorcar in the 19th century, road laws have changed considerably and cars have become much speedier, safer and more fuel efficient. Despite this, lately cars have been recorded as travelling slower, particularly on motorways.

In 2010, 49% of drivers broke the speed limit whilst travelling on motorways, a higher portion than almost any other country – Britain's 70 mph top speed limit is comparatively low compared to other European countries. However, although this seems a high figure, it is falling – in 2003 it was 57%, and since then the share of drivers exceeding the limit by more than 10 mph dropped from 20% to 14%.

Edmund King of the AA says that motorway policing has dropped by 20% in the last 10 years, so this is enforcement cannot be to blame for slower motorway speeds. Motorway traffic has also fallen, and speed cameras on motorways are also still a rare sight. So why are motorists becoming more compliant to speed limits?

A recent article in The Economist suggests people are slowing down on their own accord – explained by fuel prices having increased by 34% in real terms since 2003. According to the Department for Transport, cars use around 25% more fuel if travelling at 70 mph compared to travelling at 50 mph, and many people seem to be aware of this.

When money is tight, fuel is expensive and jobs are scarce, the average motorist will be aiming to save money wherever possible. In car technologies such as dashboard mpg dials and eco gear shift indicators provide a constant reminder that higher speeds are a less efficient way to travel down the motorway.

Drivers slowing down compliments the huge industry effort to lower CO2 and other emissions from road transport – something upon which millions of pound have been spent and countless hours of effort. However, the government has decided that speed limits should go up, and a consultation process to raise the motorway limit to 80 mph in England and Wales is underway.

If such law is passed, decades of achievements in lowering emissions will be undone, but ministers claim that raising the limit will provide "hundreds of millions of pounds of benefit for the economy".

One of their arguments is that faster speeds will increase the carrying capacity of motorways, but since the stopping distance lengthens at higher speeds then cars should travel further apart. People appear to have chosen cost savings over journey times, so this is a trend that is likely to stick. Also, the speed limit change would not apply to lorries, which are often the key part of the business network.

Many environmental groups are gearing up to lobby this decision – The Committee on Climate Change, who advise the government, are pushing to keep the current 70 mph limit in place as it is important to cut emissions. They point out that, domestic road transport accounted for 22% of all greenhouse gas emissions in the UK in 2009.

Safety campaigners are just as keen to oppose the 80 mph limit as environmentalists; many in agreement that increasing the speed limits will mean more fatal motorway accidents – something that is supported by many statistics.

Next Green Car also believes that increasing speed limits will not provide a boost to our economy, but will simply result in more road accidents and increase overall emissions from road transport – undoing years of focused effort to reduce especially CO2 from this sector.

The Economist