Lambeth will from today (4 April) be a “20mph borough”.
All roads controlled by the council will be covered by a 20mph speed limit.
“Driving slower on residential roads has been proven to reduce accidents, creating a safer environment for drivers – as well as pedestrians, cyclists and motorcyclists, who make up 80% of serious and fatal collisions,” the council said.
Cllr Jennifer Brathwaite, council cabinet member for environment and sustainability, said: “It is widely known that the difference between 30mph and 20mph can be someone’s life.
“When driving at 30mph you have far less time to react to any incident – a car braking from 30 mph will still be travelling at 22mph when one braking from 20mph will have stopped.
“By driving at a more steady speed we can all feel safer and more confident on the roads, whether we’re in a car, on a bike or on foot.”
Lambeth council is in charge of the majority of roads in the borough, apart from the major routes into and around London, which are controlled by Transport for London.
As well as all council controlled roads becoming 20mph, TfL plans to introduce the same limit on roads it manages in the borough from April, including Brixton town centre, Clapham High Street and Stamford Street.
Lilli Matson, TfL head of strategy and outcome planning, said: “We are working closely with pioneering boroughs like Lambeth who are moving ahead with borough-wide programmes for 20mph zones.”
They would not only reduce the number of road casualties but also increase active travel like walking and cycling and enhance areas where people live, work and shop, she said.
“These lower speed limits form a key part of our continuing work to make London safer, pleasant and more attractive for all.”