A consultation has been launched to see if people support Tooting and Balham becoming 20mph zones.
Up to 30,000 residents in the Bedford and Furzedown wards will be able to have a say on whether they are in favour of lower speed limits in their neighbourhoods.
Every home has been sent a detailed questionnaire and the consultation will run until Friday, April 4.
The consultations are being carried out after residents submitted petitions to the town hall asking for speed limits across the two wards.
Wandsworth Council’s transport spokesman, Councillor Russell King, said: "This is local democracy in action. Residents in these two wards will make the final decision about these 20mph zones. If a majority support their introduction then that is what will happen.
"It is only right and proper that these decisions are made by local people. It would be quite wrong to impose restrictions like this without a specific mandate and the agreement of the people whose communities would be affected by this change."
Tooting MP, Sadiq Khan, said: "For the last seven years I have been campaigning alongside local residents and Labour Councillors for more 20mph zones in our area. I am very pleased that we have finally convinced the council to take action and that the consultations for more 20mph zones have now been launched.
"I would encourage everyone who lives in the Furzedown and Tooting Bec and Balham areas to take part in the consultations, to make sure their voices are heard. Going forward, I will continue to campaign for more 20mph zones in residential areas across the rest of Tooting."
Informal consultations are also currently being held in parts of Fairfield and East Putney wards.
To submit proposals or petitions or for more information email firstname.lastname@example.org
Should Balham and Tooting drivers be forced to slow down? Leave a comment below, take part in our poll, or email email@example.com