Research from the RAC Foundation has shown that, while the congestion charge has slashed the number of vehicles entering the city by a staggering 50,000 a day, the number of appeals against incorrect penalties is set to hit 35,000 compared to the 7,000 predicted by Transport for London (TfL).
Edmund King, executive director of the RAC Foundation, said: 'The London scheme is working well in terms of traffic reduction in the centre without causing too many problems outside the zone.
'After 12 months, the mayor should be congratulated on the fact that the scheme has exceeded expectations on traffic reduction.
'But more needs to be done to measure the adverse effects on the economy of London and to improve administration so that innocent motorists are not penalised.'
The congestion charge has had a detrimental effect on businesses in the charging zone. Many have noted a slump in business as motorists have been deterred from entering by the £5 levy.
Vehicle management provider Fleetline completed research on the congestion charge, finding that 82% of small to medium-sized enterprises (SMEs) saw no benefit to businesses within the zone.