Your guide to... Motorway etiquette - Motorway facts

• The M25 is the longest ring road in the world and cost £909 million to build - that's roughly £7.5 million per mile.

• The M1 was opened in 1959 and was designed to carry 13-14,000 vehicles per day. It now carries 10 times that amount.

• At 230 miles, the M6 is Britain's longest motorway. The A635(M) in Manchester is the shortest, at just 300m long.