Motorists are to be stopped from using a main shopping street in Cardiff city centre this summer, as part of proposals to cut traffic levels.
The experiment will allow only buses, taxis, cyclists and emergency vehicles to use St Mary Street from 6 August.
If the idea proves popular, it could become permanent in 2008.
Cardiff Council's executive member for transport Elgan Morgan said it would "vastly improve the centre of Cardiff for visitors, workers and businesses".
The experimental period will affect St Mary Street, running into High Street, from the Mill Lane and Castle Street junctions.
The streets will look much the same as they do now.
Delivery vehicles will still be able to use the street at certain times
But if given the permanent go-ahead, the plans could see a widening of pavements in St Mary Street and a facelift for the area.
Mr Morgan added: "We expect the change to improve noise and air quality and reduce journey times for public transport travelling in and out of the city centre.
"This is great news for Cardiff and these changes will further enhance this historical shopping area."
Delivery and service vehicles will still be able to use the street at set times.
An exhibition of the plans will be held at the Old Library at The Hayes, Cardiff city centre on 6-7 July.