The jury is still out on whether congestion charging has been good for business ahead of the first anniversary of the £5 daily fee on Tuesday.
Businesses are mixed on the impact of congestion charging
A survey by business lobby group London First revealed 72% of businesses thought the scheme was working.
But in stark contrast the London Chamber of Commerce claimed the scheme has dealt a "substantial and negative" blow to retailers.
The chamber called for talks with Ken Livingstone to reverse the trend.
The large drop in traffic levels has left businesses desperate to find ways of clawing back cash from lost trade, the chamber said.
But London First found businesses were equally split, at 26% each, on whether the charge was having a negative or positive impact on the capital's economy.
Another 33% remained neutral on whether it was a positive economic step.
Many businesses had problems with the scheme despite 58% of them saying it was good for London's image.
London First's chief executive Jo Valentine said: "There are certainly areas for improvement, nearly half would like to see an easier system for registering and paying and a quarter of businesses said they believe that the charge had had a negative effect on the economy."
The fee applies when driving between 0700 and 1830 Monday to Friday, except public holidays, through an eight-square-mile pocket of central London.
Consultation to begin
However, Mr Livingstone has already indicated the congestion zone could be doubled in size.
A consultation starts on Monday but a decision is not expected for another year.
Plans to increase the penalty fine from £80 to £100 have been shelved until the performance of Capita, the private contractor running the scheme, improves.
Capita secured changes to its £230m five-year contract last August because it was failing to make a profit from penalty charges, but in return promised big improvements to its call centre service.
The contractor has incurred £1m in financial penalties.