Ian Gillies, the new executive member for transport at York council, said the idea was "a waste of money".
A previous council attempt to cut congestion by banning motorists from using Lendal Bridge across the River Ouse was abandoned last year.
Mr Gillies said the city had an air pollution problem but could come up with a solution itself.
"Let's take stock and see if there's anything we can do," he said. "I don't believe bringing somebody in to have a traffic congestion commission is money well spent.
"I think if we can't solve our own problems then it's a bad job."
The commission was approved by the council's cabinet as recently as February and was due to report in October. It was expected to cost about Â£135,000.
During a trial closure of Lendal Bridge from August 2013 to April 2014 to tackle congestion, general traffic was banned from using the bridge between 10:30 and 17:00.
About 47,000 fines totalling more than Â£1.3m were issued but drivers have since been told they can claim refunds.
Plans to set up a commission to investigate traffic congestion in York city centre have been shelved.