Public consultation on the future of the western extension of the congestion charge will begin later.
Londoners are being asked whether the extension should be abolished, altered or kept as it is.
The extension, implemented in 2007 by former London mayor Ken Livingstone takes in Kensington and Chelsea.
Current mayor Boris Johnson has promised to comply with Londoners' wishes, describing the consultation as an "exercise in democracy".
"Whenever I head to the west of our city I meet people with strong opinions on the western extension," he said.
"But when my predecessor held a consultation on this important issue, he completely ignored its results.
"Unlike him I have the utmost respect for the opinions of Londoners and I hope that thousands of them will take part in the consultation."
Gordon Taylor, chairman of the West London Residents' Association, said: "It's failed to reduce congestion and it's probably at best breaking even.
"It's causing a lot of economic damage to west London with at least a thousand small businesses feeling the pinch and at least 20 have closed.
"Forty per cent of the people in Kensington and Chelsea live in social housing. Many are infirm, can't get out and about and rely upon mates to visit them and they can't afford the £8 to see them."
But Jenny Jones, London Assembly member for the Green Party, said the extension had been successful in reducing traffic, emissions and encouraging people to switch to public transport and cycling.
"There is every chance that the people inside the extension zone will vote to keep it in place, as they have now seen that it improves their quality of life," she said.
The consultation will be in the form of a leaflet outlining the options and a questionnaire.
Separately, an "attitudinal survey" would be conducted across London, Mr Johnson's spokesman said, which would further gauge reaction to the scheme.