Drivers could be left in a 'farcical situation' of being fined €160 for driving at 33km/h under new rules.
Newstalk Breakfast presenter Jonathan Healy was speaking as speed limits are set to be cut on a significant number of roads as the Government seeks to reduce the number of deaths.
It comes as 127 people have died on Irish roads already this year, 23 more than by this date last year.
Limits on national secondary roads are set to be dropped from 100km/h to 80km/h, for local and rural roads it will reduce to 60km/h.
The speed limit in town centres and housing estates is set to drop to 30km/h.
Government aims to cut speed limits on roads right across the country in response to the surge in road deaths this year.
— NewstalkFM (@NewstalkFM) September 6, 2023
Jonathan said speed is just one factor to consider.
"It is a factor; there are other things such as mobile phone use, such as alcohol and substance misuse," he said.
"If you're to do this, you could create a farcical situation where somebody who's doing 33km/h and is somehow caught by members of An Garda Síochána will face a fine of €160 and get three penalty points.
"The law has to be written in such a way that it allows for absurdity, and if people are going to be prosecuted for that that is grossly unfair.
"What needs to be done here is the speed limit needs to be assessed on each individual road by the local authorities, who know the roads better than anybody else, and they can determine what is the safe limit on this road."
'Sticking up signs for the sake of it'
Jonathan said any such approach is 'pointless' if it's not enforced.
"Blankets do not cover everything; there are parts of the N71 down in Kerry where you're driving on a hairpin bend and it tells you the speed limit is 100km/h," he said.
"It's bonkers that you can impose this rule on a national level, and it is pointless without enforcement.
"If you don't enforce the rules, therefore you're just sticking up signs for the sake of it."
Presenter Shane Coleman said he believes we're coming at this from the wrong angle.
"The debate is about why we shouldn't reduce the speed limit - I find that absolutely bizarre," he said.
"It's a small thing to ask people to slow down.
"I guarantee you we'll hear the arguments: 'It's impossible to drive at 30km/h, it's people who are driving too slow who cause the accidents'.
"It's nonsense," he added.