Bus Eireann is offering free travel on International Car Free Day, which takes place on Sunday, to provide the public with an opportunity to sample the range of bus services provided.
Traffic congestion continues to be a growing problem and cost Bus Eireann €13 million last year.
Spokesperson Cyril McIntyre says Bus Eireann is pressing for bus priority routes on all major roads.
"During the last couple of years, we have put a total of 133 new city bus services in the four cities outside Dublin, all low floor design, fully accessible to wheelchairs and it's now one of the most modern fleets in Europe.
"90% of the fleet is less than five years old and fully accessible," he said.