Traffic heading for Dublin city will increase by 50,000 journeys a day in the next nine years, according to the Department of Transport.
Around 40,000 of those journeys will be by private car, unless alternatives are put in place.
The Irish Times reports that the additional traffic will require the building of 40 high-rise car parks in the city centre.
It says the Minister for Transport has ruled out a congestion charge and multi-point tolling on the M50 in favour of improved public transport links to deal with the increased volume.