The M40 motorway links London, Oxford, and Birmingham in England, a distance of approximately 89 miles (143 km). The motorway is dual three lanes except for junction 1A to junction 3 (which is dual four lanes) a short section in-between the exit and entry slip-roads at junction 4 (which is two lanes in both directions) and also between the slip-roads at junction 9 (in the southbound direction only). An Active Traffic Management system operates on the short section northbound from junction 16 (A3400) to the M42.
