Tower Bridge and London Bridge could be closed to traffic for a day in September to celebrate international Car Free Day.
Transport for London has asked if the City of London Corporation will back the event in September, which would involve closing London Bridge and Tower Bridge.
Mayor of London Sadiq Khan allocated £1 million for Car Free Day events in his budget for the year ahead.
Common councilman Marianne Fredericks told colleagues at the City corporation's streets and highways sub committee this week: "If we really want to experiment about how we remove traffic from the City this is a good opportunity."
The planned event on Sunday 22 September, coincides with the popular Open House London weekend which attracts thousands of people to get a peek behind doors of buildings which are usually closed to the public.
Officers showed councillors a map where they proposed extending the car free area on the day to include streets around Guildhall and Bank and another option which could see roads around Leadenhall Street and St Mary Axe being out of bounds to cars for the day. It could include locations of up 25 attractions open for the popular London Open House event if all the areas suggested are included.
Common Councilman Fredericks (Tower ward) said she thought the car free idea was terrific but had concerns if traffic was bumper to bumper on Mansell Street, which is part of the Inner London Ring Road with the "largest area of housing". Officers said they could manage that area sensitively.
They were also asked if the area could be extended to Postman's Park and St Paul's on the day but were told it could cause problems for essential access around Bart's Hospital.
Common Councilman Randall Anderson (Aldersgate) added: "The purpose here makes a lot of sense. In my view car free should be about showing what it could be like."
However some councillors said they were concerned about closing the two bridges for the day.
Tower Bridge was closed to motor traffic for Car Free Day in September 2001 during the mayorality of Ken Livingstone.
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