Advanced technology could be used to tackle rush hour jams, Alistair Darling has predicted.

The transport secretary has revealed he wants to develop a pay-as-you drive system based on satellite tracking devices fitted inside cars.

Darling also said he is discussing ways to cut traffic chaos caused by the school run with education secretary Charles Clarke and his officials.

Options include changing school start times and school bus services.

"If you take this morning, at 8.50am, one in five cars on the road will be on the school run. There are other things you can do to help there. We're already looking at the American-style yellow buses," he told the BBC.

"Charles Clarke and I are looking at perhaps staggering the opening of schools so that their hours are rather different."

But his big idea will, when technology allows it, use global satellite positioning as a base for a system of toll charging.

Under such a system rush hour travel would be priced the highest in a bid to cut the school run and reduce the level of commuting by car.

The system would benefit people who use their cars only on an occasional basis and cut the tax burden for many drivers, Darling claimed.

He warned Britain faced a stark choice over the coming decades; more motorways or a radical rethink.

"We have a choice in the next 25 to 30 years: either build more and more motorways - astronomically expensive, environmentally damaging, and I doubt if we could actually do it - or we take a radically different look at how we manage the system," he said.

"That is where road pricing comes in. I am convinced that unless we look at the possibility of road pricing, then future generations will not forgive us."

He pledged that the government would not make money from the idea - which could be as much as 10 years away - and highlighted the success of the London congestion scheme.

Lib Dem transport spokesman Don Foster welcomed the new sense of radicalism following Darling's remarks.

"At last some imaginative thinking from Alistair Darling. With congestion rising and costing British businesses over £20 billion a year he should have acted sooner," he said.

"Britain urgently needs measures that target the most congested areas of the country without penalising those in rural regions who often have no choice but to use their cars.

"The public needs a safe, affordable and reliable alternative to their car if Britain's roads are ever going to see a reduction in traffic and congestion."