Large stretches of Dublin's quays will be cut to a single lane of traffic for private vehicles this morning, as a bus lane comes into operation.
Bus journeys into the city are expected to be shortened by up to 20 minutes as a result.
The new Quality Bus Corridors, or QBCs, will operate between 7am and 7pm on Ellis Quay, Aran Quay, Parkgate Street and St John's Road West at Heuston Station.
Around 250 buses go through the quays during morning rush hour.
Dublin Bus says the new lanes will reduce journey times into the city by up to 20 minutes.
West Dublin commuters are set to benefit with routes as far out as Lucan, Leixlip, Celbridge, Clondalkin, Maynooth, Dunboyne and Rathcoole, expected to notice an improvement.
Journey times on bus services running between Heuston and Connolly stations are also expected to be shortened.