A 30km/h speed limit will be introduced on all residential roads between Dublin's canals following a vote by councillors.
37 City councillors voted in favour of the proposal, with eight against and two abstentions.
The new by-laws will come into force on 31 March.
The 30km limit will then be introduced in a number of other residential areas within the city council area on 31 May.
The new limit will not apply to arterial routes such as Pearse Street and Amiens Street.
The 30km limit is already in place in the core city centre.
A number of councillors expressed concern about enforcement and queried how the limit would work on individual roads.
The council's head of Technical Services Brendan O'Brien said all the roads had been surveyed.
Another survey will take place later next year to assess the impact of the by-laws.