LOWER speed limits on the M50 have been suggested in a bid to ease rush-hour congestion.
A lower 60kmph limit is one option being considered as traffic levels increase on the crucial artery.
The suggestion came from the National Roads Authority (NRA) in a demand management study conducted in 2013.
"The study examines how to maintain the M50 for the future and these suggestions we made were based on best practice," NRA spokesman Sean O'Neill said.
"One of those suggestions was to reduce the speed limit to 60kmph while another suggested multi-tolling, but as we already know the Minister has already said no to this.
"In the end we do what we are told," Mr O'Neill said.
He added that one way to best regulate traffic management flow on the M50 could be "variable speed limits".
The NRA observed that traffic on the M50 was falling into the "accordion" or "concertina" effect, which would see vehicles slowing down based on one person not following the general speed limit.
"Right now if I'm driving 100kmph and there is someone in front of me driving 80kmph, then I have to slam on the breaks. In the meantime, the whole place is slowing down", Mr O'Neill said.
Apart from speed reductions, the study conducted by the NRA suggested multi-point tolling, which would see tolls popping up in other parts of the M50.
Mr O'Neill suggested that more tolls would lead to an increase in revenue for the government but conceded that the Minister for Transport Paschal Donohoe had ruled it out.
AA Roadwatch Director of Consumer Affairs Conor Faughnan said that multi-tolling was "a very bad idea", but that he thought variable speed limits "are worth looking at".
"In relation to speed limits, at the moment when you have traffic moving in a stop-start manner, that can actually have a ripple effect. It can bring traffic to a standstill.
"So it's certainly not a daft idea. I would suggest a variable speed limit is worth considering," he said.