Introducing the controversial pay-as-you-drive scheme could cost the average British family more than £3000 extra a year, according to the Sunday Telegraph.

The Government plans, aimed at improving traffic flow but cutting the amount of time people spend on the roads at the busiest time, suggest cars will be fitted with tracking devices and their movements recorded by satellite. Motorists will be charged per mile on a sliding scale, depending on the time of day they are driving and the roads they use.

Drivers on the most congested roads at the busiest times could end up paying £1.34 a mile, and the Sunday Telegraph investigation, based on research and road-pricing models by transport economist Prof Stephen Glaister, monitored the movements of three drivers in the Midlands and worked out what they would be charged. Prices varied from 27p per mile for main roads in cities at rush hour to no charges on other roads during "off-peak" periods. prompting them to come up with the £3000 a year figure.

Areas in the Midlands are expected to see some of first road-pricing pilot schemes, but prices are expected to be higher in the South-East and London. Motoring organisations want a guarantee from the Government that any road-pricing charges will replace petrol duty, which is currently £2.11 per gallon plus VAT, as well as road tax, which is an average of £150 a year.

Prof Glaister said: "The return on these charges is that motorists will be getting faster journeys and more reliable traffic. It will reduce congestion by changing people's habits".

The new Transport Bill, expected in this month's Queen's Speech, will provide for a series of road pricing pilot schemes. Last year, the Department for Transport spent £18 million on research projects investigating how schemes could work. It now wants pilot projects running by 2010, with a nationwide scheme in place by 2015.