Question: what is the speed limit on the m5
Answer: In 1966 , at the end of the 4 - month trial of a blanket 70 mph ( 113 km / h ) speed limit on previously unrestricted roads and motorways , speed checks on the M6 in Cheshire suggested that although cars were actually being driven about 10 mph ( 16 km / h ) faster , they were still usually travelling at speeds below the new limit .