A consultation on imposing a 20mph speed limit on all central London roads managed by Transport for London (TfL) has been launched.
The scheme would see a new limit along 5.5 miles (8.9 km) of roads including Millbank, Albert Embankment, and Borough High Street by May 2020.
TfL said the lower speeds were "vital to protect people walking, cycling and riding motorcycles".
However, critics have said it would make little difference.
The plan is part of the mayor of London's Vision Zero scheme, which aims to eliminate all road deaths in the capital by 2041.
The affected roads include all those managed by TfL within the congestion zone, along with the Aldgate Gyratory.
Others measures such as increasing the height of pedestrian crossings in seven high-risk locations, such as on the Embankment and outside the Tate Britain, will also be introduced.
Transport bosses have said they also hope to introduce lower speed limits on 93 miles (150km) of streets run by TfL across London over the next five years.
Joshua Harris, director of campaigns at road safety charity Brake, said 20mph limits "give drivers more time to stop to avoid a crash and also make our streets more welcoming places to be".
However, Steve McNamara, from the Licensed Taxi Drivers Association, has said the limit will make little difference.
"Those roads are all at a virtual standstill," he said.
The chair of the London Assembly transport committee, Florence Eshalomi, said the mayor should be "more ambitious" by looking at areas "outside of the congestion charge zone where walking and cycling could be utilised even more".
Roads which would have the new limits are:
- Albert Embankment
- Lambeth Palace Road
- Lambeth Bridge
- Victoria Embankment
- Upper Thames Street
- Lower Thames Street
- Tower Hill
- Aldgate gyratory including: Leman Street, Prescot Street, Mansell Street, Minories and Goodman's Yard
- Borough High Street
- Great Dover Street
- Blackfriars Road
- Part of Druid Street (between Tower Bridge Road and Crucifix Lane)
- Crucifix Lane
- Part of Bermondsey Street (between Crucifix Lane and Tooley Street)
- Part of Queen Elizabeth Street (between Tooley Street and Tower Bridge Road)
The public consultation about the plan will run until 10 July.