Calls are being made for Oxford Street to be permanently pedestrianised after traffic was banned for a party aimed at attracting shoppers back to the area.
London Liberal Democrats said Saturday's experiment was such a success that they have set out plans of how to make the road traffic-free.
They said the change would increase shopper numbers, improve trade, cut petty crime and modernise the street.
After the July bombings visitors to the West End and sales have dropped.
Proposals by the Lib Dems include the removal of traffic on Sundays by next year then go on to ban all traffic on weekends in 2007.
In 2009 they want Oxford Street to be totally pedestrianised from the junction with Orchard Street and North Audley Street to Tottenham Court Road.
Under their plans in 2013 a tram route will run from Marble Arch through to Oxford Circus, joining the planned Cross River tramway route to Peckham and Camden ay Southampton Row.
Transport spokesman for the Lib Dems, Geoff Pope, said: "The success of the Oxford Street traffic free day on Saturday shows what is needed to encourage people back into the capital.
"It is time to give some bold, fresh, new thinking to the problems that London's premier shopping street has to face."