Bus lanes built for the new Belfast Rapid Transit Glider service come into effect on Monday for the first time.
The lanes in west Belfast will operate from 7am to 7pm Monday to Saturday.
The Glider buses do not start running until September 3, but the Department for Infrastructure said opening the lanes would give motorists a chance to get used to them.
It has chosen to open the lanes during the holiday period when the roads are quieter.
The lanes are being phased in to operation, starting on Monday when those on the Stewartstown Road, Andersonstown Road, Falls Road and Divis Street will come into effect.
The lanes between East Bridge Street and Dunlady Road in East Belfast will be introduced on July 30, followed by those in the Belfast Harbour Estate and city centre on August 6.
The Glider buses which will use the lanes have been described as "a tram on wheels" and will run approximately every seven to eight minutes, linking east Belfast, west Belfast and the Titanic Quarter with the city centre.
There will be a loading and unloading window between 10am and 2pm and vehicles with a blue badge will be allowed to stop in the lanes for up to 10 minutes to drop-off or pick up a blue badge holder.
Funeral corteges are also allowed to use the lanes, which the Department for Infrastructure said would create a "safer environment" for people to walk behind the hearse.
In March it emerged the Department for Infrastructure was to allow the vast majority of taxis into bus lanes - including the new Rapid Transit System lanes - for a year.
Class A taxis, also called private hire taxis, will be able to use bus lanes where certain taxis are being permitted as part of an "experimental scheme."
The department said the extensive trial was needed.
It said a 12-week experiment allowing taxis into bus lanes last year proved inconclusive.
A spokesperson for the Department for Infrastructure said: "Like with most new schemes, there will be a two week, one-strike warning-period during which time drivers parking illegally in these bus lanes will be issued with a warning notice."