The chicken restaurant wants to extend its drive-thru branch on Sprotbrough Road and has submitted plans to Doncaster Council asking to build a single storey extension.
But some local residents are fearful the extension will create further traffic problems in the area, with many diners already having to queue on the busy Sprotbrough Road on occasions to get into the premises and car park.
Lorraine Tolley said: "Why is it necessary to increase its size? The traffic in and out of it is already horrendous."
Another said: "I've opposed the application. The traffic at that junction is already dangerous enough."
Doncaster Council has yet to make a decision on the scheme.
The chain has a number of restaurants in Doncaster, including a newly opened branch in the town centre on High Street.