A new Costco store is coming to Thorncliffe Park, and that has some residents worried they’ll be seeing supersized traffic problems.

The new location on Overlea Boulevard near Thorncliffe Park Drive — the company’s fourth in Toronto — is set to open in 2018 at the site of the former Coca-Cola Canada headquarters.

Carol Burtin Fripp, co-president of the Leaside Property Owners’ Association, said a number of residents have voiced concerns about the project since it was proposed more than five years ago.

“We’re quite concerned that a lot more traffic is going to come through our streets,” Fripp said. “We already have the issue, not just because of the Eglinton LRT construction, but because of the development pressures surrounding us.”

Fripp pointed to a traffic study done by the project’s developer five years ago that found about five million cars a year travel on Overlea Boulevard. The study estimated the superstore and gas bar would increase traffic volume by another 2.5 million vehicles.

City council approved the project but without the planned 18-pump gas bar. The city told the developer it could re-apply to add the gas bar after the store has been in operation for a year if it provides an updated traffic study.

“The thought of the lineups for cheaper gas all along Overlea … it’s a disaster waiting to happen,” Fripp said.

Coun. Jon Burnside, whose ward includes the new Costco, said he reluctantly voted in favour of the project despite sharing concerns about its impact on traffic.

“The big challenge was with our own transportation department who said our roads could handle it,” he said. “Many of us felt that was not the case, but when you don’t have your own city department behind you, it’s very hard to fight.”

Burnside said the problem lies with the transportation department’s own threshold to accept or recommend projects.

“The bigger issue is that the transportation department basically approves developments unless there’s something we call ‘total road failure,’ which really means no car is able to move for long periods of time,” he said.

The city required the developer to make the following changes to local roadways in order to address traffic concerns.

Modifying the existing traffic signals to include the Costco driveway

Modifying the centre median to allow a left-hand turn lane from the eastbound lanes of Overlea Boulevard

Signal timing modifications along Overlea Boulevard and Laird Drive

Costco declined to comment.