M25 motorway Europe's second longest orbital road after the Berliner Ring, which is . Originally built almost wholly as a dual three-lane motorway, much of the motorway has been widened: to dual four lanes for almost half, to a dual five-lanes section between junctions 12 and 14 and a dual six-lane section between junctions 14 and 15. Further widening is in progress of minor sections with plans for managed motorways in many others. To the east of London the two ends of the M25 are joined to complete a loop by the non-motorway A282 Dartford Crossing of the River Thames between Thurrock
London the outer orbital motorway (the M25, outside the built-up area) encircle the city and are intersected by a number of busy radial routes—but very few motorways penetrate into inner London. A plan for a comprehensive network of motorways throughout the city (the Ringways Plan) was prepared in the 1960s but was mostly cancelled in the early 1970s. The M25 is the second-longest ring-road motorway in Europe at long. The A1 and M1 connect London to Leeds, and Newcastle and Edinburgh. London is notorious for its traffic congestion, with the average speed of a car in the rush hour being .