The government has unveiled proposals for road tolls that it says address motorists' concerns over in-car tracking systems and privacy. The most congested areas of Britain would be broken down into zones, similar to the system used for the London Underground. Under the outline plans Zone 1 would be the city centre, Zone 2 the inner city, Zone 3 the suburbs and Zone 4 a more rural area.Roads minister Stephen Ladyman said that zone-charging, rather than tolling individual roads, would prevent rat-running and it would also answer motorists' concerns that their journeys could be tracked mile by mile. Instead of needing to know exactly where each motorist was, the authorities would only need to know in which zone a driver was. It’s likely that all cars would carry a small ‘tag’ charge card mounted inside the windscreen, similar to those used on French and Italian motorways.As a driver crossed a zone boundary, the fee would be automatically deducted by roadside ‘beacons’.Every car in the UK would have an account tied to the registration plate, because the fee is likely to be varied depending on the vehicle’s CO2 output.Autocar understands that Transport for London is already working on similar proposals for Greater London.According to hints about the capital from Ladyman, it’s thought Zone 4 would be inside the M25, Zone 3 inside a new proposed Low Emission Zone, Zone 2 inside the North and South Circular roads and Zone 1 the existing congestion charging area. It’s also possible that a Europe-wide tolling system could be implemented by 2011.