A LEADING North Yorkshire road safety expert has questioned the decision to impose a blanket 20mph speed limit across York.

Former police accident investigator Mike Natt said factors other than speed should be considered when assessing how to prevent road casualties and deaths as City of York Council presses ahead with plans to make York a 20mph city.

By the end of 2014, the 20mph limit is likely to be in place across much of the city, starting with South Bank. Some major roads into York and some outlying villages will remain 30mph.

Coun Dave Merrett , the council’s cabinet member for transport, planning and sustainability, said the limit – to be enforced in the same way as 30mph –was a bid to reduce accident numbers. But it also aimed to make York more pleasant for walkers and cyclists, which may also help tackle the city’s transport problems, he said.

York city councillor Anna Semlyen, a 20’s Plenty For Us campaigner, said a 20mph limit was right for York because it was easier to react to a potential hazard at slower speeds, making it safer for walkers, cyclists and people of all ages, including the most vulnerable, as well as cutting pollution and congestion.

But Mr Natt, an independent collisions investigator who served for nearly 30 years in North Yorkshire Police’s traffic department, filing reports on hundreds of fatal accidents, said in a piece written for The Press today that pedestrians sticking to the Green Cross Code would save more lives than “20’s Plenty”.

He said he would like to see more railings installed to prevent people walking on to roads rather than a city-wide speed zone.

Statistically, people were less likely to be killed if hit by a vehicle travelling at 20mph than by one at 30mph, but “this does not tell the whole story”, said Mr Natt.

At speeds above 40mph the pedestrian passes on to or over the roof of the vehicle, he said.

At lower speeds, in the 20mph to 30mph range, the pedestrian is rolled on to the bonnet, then knocked forwards and away as the vehicles brakes.

Mr Natt said: “At speeds of 12mph or less, however, the pedestrian is pushed forwards down on to the road ahead of the vehicle, which then runs over them, causing serious injury or even death. Children, due to their height, are even more at risk.”

Each collision is different, with factors such as location and whether an adult or child was involved affecting the outcome.

Former council leader Steve Galloway said a blanket 20mph speed limit across the city would be expensive and undo the work to tackle speeding carried out by the previous Liberal Democrat council, which introduced 20mph limits at potential accident locations, including outside all of York’s schools.

He said: “I, and the party, continue to oppose a city-wide 20mph limit.

“We favour the policy of having the most appropriate speed limit bearing in mind individual characteristics of individual roads, based on the fact that it would be very expensive to implement, with figures of £600,000 quoted.

“The money would be better spent continuing the council’s previous successful work reducing the number of people killed and injured on York’s roads, not only to ensure the correct speed limit was applied, but the money would be invested in engineering works to ensure roads were safer and where appropriate to enforce existing speed limits.”