The voluntary scheme, due to start next term, will even apply to the Volvo-driving families whose children attend private schools.
The council wants to build on ideas developed with the independent Royal primary school, in Hampstead. The Royal was allowed to take on more pupils in return for drawing up a green transport plan.
Measures included putting parents who were interested in car sharing in touch with each other.
Alex Williams, head of traffic programmes at the council, describes the iniative as "an important and innovative scheme to cut pollution and improve the quality of life in the borough".
Journeys to school accounted for 20 per cent of all traffic in the afternoon peak period and tackling it was an important part of cutting congestion. The Royal had managed to cut car use by 23 per cent in one year and he hoped other schools would follow suit.
To overcome safety fears adults would be encouraged to walk home with a group of children.
Patrick Crawford, a form teacher at Maria Fidelis RC School, said pupils raised the policy when they met councillors. "They were very concerned about the policy. The girls would prefer an alternative to using a car but they felt cycling was not safe and public transport was in a sorry state and they felt unsafe walking home from bus stops at night," he said.