The ban on heavy goods vehicles (HGVs) led to delays around the M50 early this morning.
According to the AA, southbound traffic on the M50 was very slow from the M1 intersection through to the Lucan exit during peak time, with slower-than-normal delays also experienced from Ballymount to Firhouse.
Traffic was also very heavy on the M1 southbound from before the airport turnoff through to the M1/M50 intersection. Motorists reported delays of over an hour approaching the M1 from the Malahide Road and N32.
The AA said that M50 northbound traffic was also much heavier than normal with delays from Dundrum to Finglas. By 10am delays had dramatically eased, however, apart from the M50 southbound, which remained heavy from Finglas to Lucan until after midday.
The new truck ban has been introduced by Dublin City Council to reduce the number of large lorries in the city, particularly on the congested city quays, by forcing them to use the Dublin Port Tunnel.
Five-axle HGVs are banned from a cordon that includes the area between the Royal and Grand canals, as well as Sandymount, Ringsend and part of the Navan Road from 7am-7pm daily.
It is estimated up to 2,000 HGVs a day will be removed from Dublin city streets from 7am today, and a large number of these will divert on to the M50.
Hauliers who break the cordon without a permit face fines of up to €1,500 and imprisonment.
However, the council has agreed to pay the tolls on the East-Link bridge - in which it is a shareholder - at a cost of up to €1 million a year for HGVs that have to use the route to access the south port.
Hauliers have claimed the ban will cause chaos on the motorway.
Fine Gael spokesperson on transport Olivia Mitchell called for the Port Tunnel to be opened up to public transport. Ms Mitchell claimed that thousands of cars were being forced off the M50 as a result of the increase in HGVs now using the motorway.
"This futile transposing of traffic from one congested area to another highlights the folly of building an expensive tunnel without implementing a Dublin-wide transport plan or any co-ordination of projects," she said.
"The irony is that the traffic snarl-up happened during the mid-term break, when Dublin's traffic is supposed to be lighter."
According to Ms Mitchell, the liberalisation of the Dublin bus market to allow private operators into the market would be the solution.
"The way to sort out this mess is by providing immediate public transport alternatives for weary commuters. Buses represent the cheapest and most effective way of doing this," said Ms Mitchell.