Traders in east Belfast have said the true impact of a new traffic scheme will only become clear after the school holidays.
Controversial bus lanes went into operation for the first time on the Upper Newtownards Road yesterday, one of the city's busiest routes.
The new lanes, which run between Sandown Road and Knock Road as part of the Belfast Rapid Transit (BRT) scheme, will operate in both directions from 7.30am until 9.30am and 3.30pm until 6.30pm, Monday to Friday.
The Department for Regional Development (DRD) said they "will help to provide a more reliable service".
Local business owners have said they are reserving judgment on the potential effects of the bus lanes on trade in Ballyhackamore.
Doreen McKenzie, who has been running a travel agent's there for 35 years, said the road was deserted at 8am yesterday, but by 9am the traffic was tailed back the whole way through the village.
"It's a good time for the bus lanes to go operational because the schools aren't back yet and people can get used to the new system," she said.
"But I am worried that it may become very difficult to drive and park in Ballyhackamore, which means shoppers won't come.
"The traffic lights could also slow things down, and there might also be potential problems with delivery lorries stopping in bus lanes.
"But the upside for us is that it might bring more tourists into Ballyhackamore during the day.
"We already have a booming night-time economy with the bars and resturants and we'd like to attract shoppers to the village during the day as well."
Denise Shields, chairwoman of Ballyhackamore Business Association, runs the Barista Coffee House at the edge of the new bus lane.
She said there had been a mixed reaction to the new lanes, but added that day one passed off smoothly.
"The scheme was intelligently launched when the schools are still out and the traffic seems to be moving well enough, but we'll have to wait for a couple of weeks to see how things pan out," she said.
Ukip MLA David McNarry, who sits on Stormont's regional development committee, said motorists were being "pushed off the roads".
"Introducing the new bus lanes in Ballyhackamore is a disaster waiting to happen," he said.
"There are five schools in that area. It's going to be a nightmare. They're putting the lanes in at peak times and I'm very worried about safety. Buses have been seen speeding in the area and a young child was involved in an accident quite recently.
"But we have to send out a positive message that people should still go to Ballyhackamore, but they need to give themselves an extra 15 minutes per journey."
Northern Ireland Independent Retail Trade Association (NIIRTA) boss Glyn Roberts said it was worried about congestion and gridlock in the area.
"People should consider leaving their cars at home because we need to keep the roads clear for shoppers coming into the city centre," he said.
"The biggest challenge for Belfast is parking. We need a proper strategy."
East Belfast MLA Judith Cochrane said she too had concerns.
"No one has been complaining about them so far but it will become more of an issue when schools go back in two weeks," she said.
"I don't think people will notice the difference in terms of traffic movement."