The number of gardaí involved in Roads Policing Units has dropped by nearly 40% since 2009, the latest figures released from the Department of Justice and An Garda Síochána have shown.
The figures were released in response to a series of parliamentary questions by the Fine Gael TDs Michael Murphy and Emer Currie, and come amid concerns raised by road safety advocacy groups.
The number of overall personnel has decreased from 1,046 in 2009 to 645 in March of this year - a reduction of 401 specialised gardaí policing Irish roads.
Dublin's number of gardaí in the units almost halved during this period, with a decrease of 45%, or 130 fewer personnel.
DMR South Central has seen a decrease of 59% over the 17 years, with 16 fewer specialist roads policing gardaí, the figures covering up to the end of March show.
The division of 11 gardaí has two road policing vehicles.
Sligo/Leitrim also recorded a large decrease, falling from 34 gardaí in its unit in 2009 to 14 this year.
Limerick was the only county where the number of personnel is not down - with one more garda in its Roads Policing Unit than there was in 2009.
A group representing people who have lost loved ones in fatal traffic collisions has called the declining numbers "heartbreaking".
The founder of PARC, Susan Gray said the former garda commissioner "told an Oireachtas committee two years ago that he was going to address this" and "he failed".
"They haven't got the resources they need to make the roads safer. We need them and they are being depleted," she said.
In a statement, An Garda Síochána said all gardaí "even those outside of full-time Roads Policing Units, have a role to play in the enforcement of road-traffic offences and do so on a daily basis".
It said last year non-full-time roads policing personnel were responsible for over 60% of DUI detections, 65% of vehicle detentions, and 80% of checkpoints carried out.
A spokesperson said there is no organisation policy to reduce numbers in Roads Policing Units, and it has allocated over 80 members to units in the last 18 months.
"This is the largest allocation of new personnel to any specialist unit in the last 12 months and roads policing has the largest number of personnel in any specialist unit in An Garda Síochána," they said.
An Garda Síochána said it also has to allow for "other organisational demands and policies" but will deploy additional members to "priority areas" as they become available.
At an Oireachtas Committee on Transport last October, Deputy Garda Commissioner Shawna Coxon said it had not had the desired "significant uplift" in roads policing numbers.
