There are fears that Cardiff will not be able to cope with the increased traffic one of south Wales' biggest stores will generate when it opens next week.
The Cardiff store will be the second largest in the UK
Ikea, the Swedish furniture giant, expects to welcome 15,000 people a day following its opening in the capital.
The company has given Cardiff council £3m towards traffic improvements.
But local residents say they are deeply concerned that this will not be enough.
The Ikea store, which sells home furnishings, is the first one to be opened in Wales - and will be the second largest in the UK.
Wherever they have opened, the stores have been hugely successful, and store-manager Theresa Daly believes the one in Cardiff will be no exception.
Council contractors are working around the clock widening roads and roundabouts and putting in new traffic lights.
But residents who live near Cardiff industrial estate where the store has been built say more needs to be done.
It is estimated that almost two million people live within an hour's drive of the store.
Ikea founder Ingvar Kamprad
But it can only be accessed via the M4 to the west, through Cardiff Bay and through Grangetown.
There are also fears that the city could experience gridlock when the store opens on November 6 as the Wales Rally GB begins in the bay on the same day.
Organisers are working with the county council to try to avoid traffic chaos but senior councillor Michael Michael has warned people to expect delays.
"Routes into the site are likely to be busy, especially around the Ferry Road junction of the A4232, and we would encourage residents and visitors to the city to plan their journeys carefully and to allow plenty of time to reach their destinations," he said.
The Ikea store has a 1,200-space car park, but it is expected that all spaces will be filled early on in its 12-hour opening day and the weekend following.
A spokeswoman for the Swedish furniture giant said that a number of initiatives were being discussed to help ease congestion.