A spokesperson for City Hall said officials met yesterday to discuss introducing the move across parts of the city's 32 boroughs this year - some car-free days already exist for events such as the London Marathon and Pride events.
Throughout recent months, Mr Khan has shown concern over the building limitations that London councils face, when trying to replace the homes that were sold under Right to Buy. Council homes for social rent bind our city together, and they have been built thanks to the ambition of London's councils over many decades.
In what will be the first ever City Hall programme dedicated to supporting council housing, Sadiq is using funds from the £1.67bn he secured from government in the Spring Statement to help support London's councils to increase dramatically the rate of council homebuilding in the capital.
London councils have only built 2,100 homes over the last seven years and a total of 300 were completed in 2017.
Sadiq Khan spent most of his upbringing living on a council estate and has witnessed the importance of social housing in London first-hand.
"I will do all I can to help councils replace as many of them as possible".
Clare Coghill, leader of Waltham Forest Council said: "This money will give a massive boost to the number of council homes we can build helping to reduce the thousands of people on our housing waiting list and achieve our priority of putting a decent roof over our resident's heads".
Back in the 1970s, when I was growing up, London councils built thousands of social homes, providing homes for families and generations of Londoners.