Ireland's motorways are eight times safer than three-lane roads, according to new research at UCC, writes Dick Ahlstrom
Motorways are the safest roadways in the State despite the higher speeds travelled on them, according to new research from University College Cork. The most dangerous are three-lane roads (those with a climbing lane) and undivided two lane roads, the study concludes. The study also provides proof that traffic-calming measures taken in villages along national primary routes cut accident rates and help save lives.
The new research is the first comprehensive study of accident rates on Irish roads as related to road type, according to Dr Donncha Ó Cinnéide, who led the research. Dr Ó Cinnéide heads the traffic research unit within UCC's department of civil and environmental engineering. "It was a combined thing with the National Roads Authority," he says. "We wanted to establish accident rates on Irish roads."
Before the study, UK figures were used to anticipate accident rates here, but now local statistics have been compiled that give road planners some figures for anticipated accident rates given road type and physical characteristics of the roadway and surrounding "road elements". These include lane width, hard shoulder, medians, intersections, verges, grades, curves and passing sight distance.
"It has been done over the last three or four years," says Dr Ó Cinnéide who was assisted in the project by postgraduates, Judith Murphy and Terence Ryan. "We looked at the inter-urban roads outside the 40 mph zones."
Use of UK statistics is not that helpful, given significant differences between typical Irish and UK road use, explains Dr Ó Cinnéide. In Ireland, 70 per cent of all driving is done outside the urban 40 mph zones, while in Britain the majority of driving is done inside this low speed zone. "We have a lot of high-speed travel on undivided two lane roads," he says.
The team used the extensive databank of information held on computer by the National Roads Authority. Separate systems hold information on every stretch of national roadway and comprehensive statistics on accident rates.
Dr Ó Cinnéide and his co-workers had first to "clean up" the data so that the data sets were comparing like with like. They then linked the accident information with the roadway data so accident rates per 100 million kilometres travelled could be determined.
In the process they discovered that there is serious under-reporting of accidents, something that made the project difficult. While almost all fatal accidents are reported, many injury accidents, especially those involving minor injuries, are not, he says. Dr Ó Cinnéide estimates that only about one third of these minor mishaps are reported to the Garda.
Their findings show that motorways are indeed the safest road type despite the high-speed travel. "Motorways are best of all and much safer than other roads," says Dr Ó Cinnéide. "It seems our motorways and dual carriageways are safest," he adds, with most road types experiencing accident rates "much the same as the UK" for the number of kilometres travelled.
Three-lane roads with climbing lanes were particularly dangerous they found, with a fatal accident rate eight times that for motorways. About 10 per cent of all injury accidents on three lane roads result in fatalities. Undivided roads were six times more dangerous than motorways and dual carriageways three times more dangerous.
These figures add weight to arguments being made for physical barriers to improve safety on undivided roadways. Continental drivers are familiar with three-lane roads that alternate, with the third lane being given to one side for several kilometres, then the other. In Sweden, a physical wire barrier is also provided on many such roads to make them even safer.
The research also showed that traffic-calming in towns and villages along national primary roads is helping to save lives.
Traffic-calming on these routes caused a 47 per cent reduction in the accident rates in these towns, Dr Ó Cinnéide found, with average speeds reduced by about 12 km per hour.
Dr Ó Cinnéide's conclusion from the results is that the State needs more motorways and more traffic calming. "The National Roads Authority is right to try to build as many motorways as possible because they are safer. We are in favour of what the NRA is trying to do."