Dublin City Council plans to reduce speed limits through much of the city centre from 50kph to 30kph as part of its proposals for new speed limit bylaws.
It also intends to increase the speed limit on the N11 Stillorgan Road from 60kph to 80kph - but only on one side of the dual-carriage way.
The council has the power to introduce new speed limits on certain roads in line with guidelines issued by Minister for Transport Martin Cullen to all local authorities in April.
Proposals put before the council's traffic committee by the city's director of traffic Owen Keegan recommended the introduction of 30kph limits on O'Connell Street, the suburb of Marino, and in parts of Ringsend and Irishtown as a pilot scheme.
However councillors voted to widen the pilot area to include most of the city centre from Parnell Street to St Stephen's Green, excluding the Liffey quays.
The council says the lower speed limits will help reduce the number of pedestrians killed on the roads.
Statistics from the UK department of transport which were used by the council show that a vehicle hitting a pedestrian at 50kph results in death in some 45 per cent of cases. If the speed is reduced to 30kph the likelihood of a fatality is just 5 per cent.
The speed limit proposals will be put to public consultation in around four weeks' time.
It is expected that any new limits will be in place in three to four months.