Toll roads are rare in the United Kingdom, though there are a number of toll bridges. Road traffic congestion has been identified as a key concern for the future prosperity of the United Kingdom, and policies and measures are being investigated and developed by the government to reduce congestion. In 2003, the United Kingdom's first toll motorway, the M6 Toll, opened in the West Midlands area to relieve the congested M6 motorway. Rod Eddington, in his 2006 report "Transport's role in sustaining the UK's productivity and competitiveness", recommended that the congestion problem should be tackled with a "sophisticated policy mix" of congestion-targeted road pricing and improving the capacity and performance of the transport network through infrastructure investment and better use of the existing network. Congestion charging systems do operate in the cities of London and Durham and on the Dartford Crossing. In 2005, the Government published proposals for a United Kingdom-wide road pricing scheme. This was designed to be revenue neutral with other motoring taxes to be reduced to compensate. The plans were extremely controversial; 1.8 million people signed a petition against them.