SERIOUS collisions on 20mph roads have increased by more than a quarter in the last year, according to the Institute of Advanced Motorists.

According to analysis of government data by the road safety charity serious collisions have increased by 26 per cent while slight accidents on 20mph roads increased by 17 per cent.

The data also shows a decrease in the number of serious and slight accidents on 30mph roads and 40 mph roads with serious accidents down nine and seven per cent respectively.

There was a five per cent reduction in slight accidents on 30 mph roads and a three per cent decrease on 40 mph roads.

Serious casualties on 20mph roads have also increased by 29 per cent with slight casualties up by 19 per cent.

IAM chief executive Simon Best said: “More and more roads are being given a 20mph limit but they do not seem to be delivering fewer casualties.

“The IAM are concerned that this is because simply putting a sign on a road that still looks like a 30mph zone does not change driver behaviour.

“More evaluation and research is needed into the real world performance of 20mph limits to ensure limited funds are being well spent.”

Mark Tilley, assistant director for infrastructure at Wigan Council, said that the council will be closely monitoring the number of road collisions in 20mph zones.

“As the introduction of the 20 mph areas is relatively recent, we do not yet have sufficient data to make a fair assessment of the impact of the scheme,” he said.

“I would stress road collision data is subject to random fluctuations and comparing short time periods does not yield quantifiable results of which we can draw a conclusion from.

“We introduced the 20 mph areas because the evidence overwhelmingly suggests collisions at 20 mph are much less likely to prove life-threatening.”