It has been dismissed as a token gesture by environmentalists and public transport campaigners because it is happening on a Saturday, but today is the second European Car Free Day and motorists here are again being urged to leave the car at home.
Those who would usually get behind the wheel in the daily effort to go nowhere fast have been asked to walk, cycle or take public transport instead.
Officially, 10 cities and towns are participating in the initiative, which is promoted by the European Commission. Some streets will be closed to traffic, albeit on a "voluntary" basis in some areas.
In Galway city, the local authority will have staffed barriers closing off the majority of central streets. However, a spokesman said this week that if people insist on getting through, they would be allowed.
The other urban centres participating are Cork, Dublin, Limerick, Waterford, Saggart, Portlaoise, Clonmel, Greystones and Sligo.
Street activities and entertainment have been organised to promote it. However, environmental campaigners say the event serves only to highlight the failure to implement real alternatives to motor traffic.
Dublin motorists will still be able to drive relatively unihindered around the capital, as there will be hardly any road closures on the day.
Custom House Quay, outside the Department of the Environment's headquarters, will be closed from 7 a.m. to 7 p.m. and Merrion Square West will be blocked off to traffic from 9 a.m. to 5 p.m.
However, the so-called Critical Mass campaign, a network of cyclists who have been campaigning for better facilities in Dublin, will take to the streets of the capital at 2 p.m. and do a lap of the city.
Mr Geoff Corcoran of Critical Mass, which stages cycling protests on one day each month, said he expected around 300 cyclists to participate.
Galway's road restrictions in most central streets will operate on a voluntary basis, relying on the goodwill of motorists to enter into the spirit of the occasion.
The Galway Cycling Campaign has declined to become formally involved with the corporation's activities today.
It says it feels "uncomfortable with being involved with the scheme at a time when there is an absence of concrete measures to improve the safety of cyclists in the city".
Cork will close most of its central streets and Limerick and Waterford will close some streets in the main city areas.
Public transport providers are also doing their bit. Just for the day, Dublin Bus will charge a flat fare of 60p for adults and 40p for children and Iarnr≤d ╔ireann will offer half-price family day "rambler" tickets.
Green Party TD Mr Trevor Sargent dismissed the event as a "publicity stunt".
"I see it as being fairly meaningless from the point of view of indicating what Dublin or other cities might be like with fewer cars. They are only closing off an area around the Custom House, which is a bit like the minister just closing off his front garden.
"The car-free day should be a way of providing, say, a target date for providing bike shelters and lock-up facilities or for the bus companies to have a certain number of bike racks on the back of buses.
"Local authorities could also have it as a target for providing more park-and-ride facilities," he said. Other European countries were "much more radical" about the initiative than Ireland, Mr Sargent added.
Some 961 municipalities within the EU and outside it will take part. In Belgium, the event is being extended to a national week of sustainable mobility, which runs until September 30th.
In Paris, road closures will cover 2,841 hectares and affect 230,000 inhabitants, according to the website set up to provide information on the event.
Traffic speeds will be limited to 30 k.p.h. in the city and the police will monitor the 150 access points.
European Car Free Day has a website at www.22september.org with links to national sites.