Operation Freeflow, the annual traffic management programme in Dublin city, will be officially launched this morning.
However, 160 recently trained gardaí have been on duty at key junctions around the city since Monday.
AA Roadwatch spokesman Conor Faughnan said the annual traffic management programme for the capital remained worthwhile.
"Our main complaint is it doesn't run all-year round. It shows what is possible with dedicated enforcement.
"If we get a wet day or a crash on the M50, we will no doubt hear people complaining about it, but without Freeflow, things would be a lot worse," he said.
Insp Eddie Murphy from the Garda Traffic Control Centre said gardaí would police over 100 junctions from 7am until 9pm weekdays and between 10am and 8pm at weekends until January 4th, when the operation ends.
New areas of the city have been added to the programme this year, with 10 gardaí assigned to junctions in Balbriggan, Co Dublin.
Mobile Garda units and a Garda helicopter will also be involved during peak times.
While non-essential roadworks have been suspended, the M50 upgrade and Docklands Luas works will not be halted.
However, the Sandyford Road is reverting to a two-way route for the next six weeks and roadworks around John's Road near Heuston Station have stopped.
There will be additional late-night Luas and Nitelink services during Operational Freeflow and these will be policed by a team of gardaí.
While the Dart will not run late-night trains, there will be additional weekend capacity, an Iarnród Éireann spokesman said.
Insp Murphy said the local authorities in the Freeflow area had been asked to repaint 120 yellow boxes. "We are asking motorists to keep these free. It can cause mayhem when a vehicle is stuck in there, particularly a bus or a truck."
Calling on drivers not to drink and drive, Insp Murphy said gardaí on duty at the junctions would all "have access to" breathalyser equipment, adding that they had been instructed to use common sense.
"We don't want them arbitrarily stopping people."
Michael Ahern, senior transportation planner with the Dublin Transport Authority, said the number of people using public transport was expected to rise this year, due in part to longer carriages on the Luas Red Line and special late-night Luas and Nitelink services.
An extra 20,000 people a day were expected to use public transport over the period, he said.
One of the challenges for the organisers was managing people's expectations, Mr Ahern added. "On one day last year there were 19 crashes. All people see is that there is some congestion. What they don't see is the reason," he said, adding that "Freeflow is not going to solve the transport problems of a region".
There are no bus-based park- and-ride facilities this year. Details of the rail-based park and ride will be announced later in the week.
These will be posted on the dedicated website www.freeflow.ie which will provide information on all public transport services, including bus and train timetables, Luas stops and maps. It also has guides to major shopping routes and a detailed list of approved parking.
