The more major of the current roads often started as turnpikes in the 16th century. These avoid the highest areas of the hills. To the north of the western part of the Mendips, the A368 separates the hills from the Chew Valley, while on the southern edge the A371 similarly runs along the bottom of the scarp slope between the hills and the Somerset Levels. The western end of the hills is crossed by the M5 motorway with access at junctions 21 and 22, along with the A38. Further east, and running almost north to south, are the A37, A39, A36 and the A361.