PLANS to ban smoking in cars carrying children would be "labour intensive" and have little effect, according to a new study.
The study, which involved observing 2,230 drivers, found they were more likely to be using their mobile phones than smoking.
Health Minister James Reilly has indicated his intention to ban smoking in cars which are carrying children under 16, although there is yet no date for when it will come in.
The study by the UCD School of Public Health, Physiotherapy and Population – which involved observing cars over three time periods in two Dublin locations – found the prevalence of mobile telephone use was 2.56pc while it was 1.39pc for smoking.
The more expensive the car the less likely the driver was to be smoking, according to the researchers.
"It was low for both. Eight adult passengers and just one child were observed as being exposed to a smoking adult driver," the findings, published in the 'Irish Medical Journal', said.
It suggested that the "resources required for a ban in vehicles may be labour intensive for the yield in detection or prevention."
The study pointed out that in 2006, a ban was introduced prohibiting the use of handheld mobile phones while driving.
"Again there is very little systematic evidence from Ireland on the number of people who still do so regardless of legislation.
"One study found that mobile telephone use while driving was associated with a four-fold increased risk of having a motor vehicle collision."
The two locations chosen for the observation exercise were outside St Vincent's Hospital in the south side of Dublin and the Mater Hospital in the north inner city.
"Smoking rates decreased markedly as the value of the car rose, from 2.05pc in the lowest quartile of value to 0.5pc in the highest. No significant association with car value was observed for mobile telephone usage."
It said: "Mobile telephone usage is already legally prohibited but we observed low but appreciable continued use, which was greater in the more affluent observation point. Other surveys in the country report somewhat higher, but comparable rates.
"There is immediate danger to road users from this practice and it is policed with penalty point sanction, though clearly difficult to enforce absolutely."
The study concluded that if a smoking ban in cars with children is introduced it would "take serious consideration by An Garda Siochana as to how in practice this might operate. It is possible that the existing legislation has already indeed had an impact on the practice since social support for that legislation is already very strong".