Early next year the Department of transport will begin field trials of electronic equipment with a view to charging tolls on Britain’s motorways. If the equipment works, the plan is to apply the system nationwide by the end of the country. A very small charge, initially set at about a penny per kilometre, will raise a billion pounds or more a year. The Department of Transport says that this will be used to help pay the costs of improving the motorway network. Tolls eventually will be varied by time of day, to reduce congestion and to spread traffic demand more evenly. They may also be extended to trunk roads and even to local roads.