Ken Livingstone has launched his transport manifesto for the May London elections, pledging to create greener and more personalised services across the capital.

The mayor said if re-elected he would put a fleet of 500 hybrid buses, which cut emissions by up to 40 per cent, on the roads by 2010 with a view to making all buses hybrids by 2012.

He also outlined £500m of investment to create a "revolution in cycling", making it safer to ride a bike in the capital by creating cycling zones and routes linking schools, residential areas and workplaces.

Livingstone pledged to introduce a hire scheme to make 6,000 bikes available every 300 metres which would be free to use for the first half hour.

Warning of a potential "disaster" if large projects went wrong, the Labour candidate pointed to an alleged £100m a year error in his Conservative opponent Boris Johnson's transport plans.

"The biggest task confronting the mayor over the next four years is to successfully deliver the huge transport projects that are now underway in London - because these are the key not only to moving around the city but to the entire finances of London," he said.

It was vital to continue the £16bn Crossrail project, the £1bn a year tube modernisation and the expansion and improvement of London's bus system, Livingstone argued.

"If schemes like Crossrail, the bringing of local rail services under London's control with London Overground, Tube modernisation and the management of our buses go wrong, they are so large they will create not only a transport but a financial disaster for London with huge rises in fares and business rates. This, therefore, matters to every Londoner," he added.

"I am running on my record of successfully delivering major improvements in London's transport system in the last eight years and on delivering the even bigger schemes to come."

Very low polluting cars would be exempt from the congestion charge, and the mayor said that the £25 levy for gas guzzlers would cut emissions and raise at least £30m a year for public transport, to be spent on making improvements to cycling and walking.

He also pledged to maintain free travel for children, introduce a 24-hour Freedom Pass to give older and disabled passengers free travel throughout the day and extend student discounts.

Johnson accused Livingstone of "making promises on transport to try to save his job".

"The problem is that we've heard it all before from this mayor - inflated promises before an election which are broken straight after," he said. 

"This Labour mayor says judge him on his record, claiming he is the man to deliver. Well his administration has consistently fallen behind with major projects or gone way over budget costing Londoners millions. What kind of record is that to be proud of?"