Claims road works in Derby are causing problems for businesses in the city have been backed by new figures.
Some shop owners had said customers were going to Nottingham and Burton instead to avoid delays and congestion.
Derby's Chamber of Trade said June sales in the centre had fallen 2.5% compared to last year, despite there being rises nationally.
The city council said it would do all it could to minimise disruption and the impact on traders.
Patience requested
The Chamber's Chief Executive Ian Ferguson said: "The market is very sensitive and it doesn't take much for people to be put off coming into the city centre.
"Things are changing all the time, road works are moving and certainly the congestion was worse this month than last."
Mr Ferguson admitted there were many factors which could affect sales but pointed out that businesses that had branches on city outskirts found these had done better.
The city council said it met with the chamber on a regular basis to discuss any problems and asked people to bear with them while the city centre was improved.