20mph speed limits are being introduced across roads within the Royal Borough of Greenwich, Lewisham, Southwark, and Bromley.
The new speed limits were initially introduced in September and will continue until the end of December.
According to TfL, each year in London, more than 1000 people are injured or killed by drivers exceeding the speed limit.
Lowering speed limits is a part of the Mayor's ‘Vision Zero’ goal to reduce death and serious injury.
This is part of TfL’s campaign to tackle speeding and encourage people to walk or cycle in London.
Below are the roads where 20mph speed limits are being introduced in south east London and how much it has cost TfL.
West Wickham town centre 20mph £38,883
A205 in Greenwich 20mph £128,290
Southwark TLRN 20mph £251,992
Lewisham TLRN 20mph £198,421
A20 in Greenwich 20mph £118,337
The new speed limits are set to make a large area of south east London safer and more attractive for people in these communities to live and work in.
Once the works on the new speed limits are finished, TfL will have delivered 140km of 20mph roads, ahead of its target to do this by May 2024.
New signs and road markings will show the new speed limits, as well as banners on street lamps in the 20mph zones.
Transport for London (TfL) is working with the police to make sure drivers follow the new lower speed rules.
Walking and Cycling Commissioner, Will Norman, said: "Lowering speeds is one of the most important things we can do to reduce road danger and forms a key part of the Mayor's Vision Zero goal to eliminate death and serious injury from London's transport network.
“TfL data shows that 20mph speed limits are reducing the number of collisions on London's roads, which is why I'm pleased the 20mph programme has been expanded, helping to make a large area of south London safer and more attractive for people to live and work.
“Every death or serious injury on our streets is devastating, bringing heartache and tragedy to all those involved so we will continue to work with TfL, the Met Police and London's boroughs to make it easier and safer for people to walk, cycle and use public transport, creating a safer, greener London for everyone."