THE controversial 30kmph speed limit introduced to Dublin city is expected to save the state over €3m a year. Efforts are now being made to extend the initiative nationwide.

The Irish Medical Organisation (IMO), which has written to every local authority in the country requesting the same initiative be put in place, has said it could be as significant to saving lives as the recent introduction of mandatory road-side breath testing.

Citing research published last year, Dr Declan Bedford, a public health specialist and former IMO president, said that deaths in built-up areas could be virtually halved with significant savings to the economy. "Many other cities around the world have done this, it's not new. In Graz in Austria, they introduced it to the whole city in 1992," he said.

A study published in the British Medical Journal earlier this year said the introduction of a 20mph (32kmph) limit around London between 1986 and 2006 led to a reduction of 42% in road casualties. The figures rose to as high as 48.5% for children.

The journal noted "that 20mph zones would prevent 200 casualties and 27 deaths a year" and recommended introducing 20mph zones in major cities in Britain and elsewhere. "Traffic deaths are projected to be the fifth-leading cause of death worldwide by 2020, and excessive speed is considered the single-most important contributor to road fatalities."

While a recent survey conducted by the Sunday Tribune found that a substantial number of motorists disobeyed the speed limit in the city area, Bedford put this phenomenon down to poor communication.

"It needs to be implemented and publicised. Looking at Dublin, it's very hard to see where it starts and ends and there are very few reminders in the middle. It needs to be signposted," he said.

Bedford said there were eight fatalities and 461 injuries from motor accidents in the Dublin city area between 2003 and 2007. Noting a study by Goodbody consultants examining the economic costs of road accidents, he said that if that number were halved, it would translate to an economic saving of around €16.8m or €3.3m a year, in that area alone. "That would buy a lot of signs," he said.

There would also be significant health benefits, according to the IMO. Two out of three Irish adults are either overweight or obese and a reduction in city speed limits would encourage many to walk or cycle.