Birmingham, Oxford M40
16
Watford, Amersham, Maple Cross M25

Change Route: M40 North or M40 South

This intersection was built in a low level style to reduce impact on the Alderbourne valley. The next section was opened in January 1985 and cost £20m. The two carraigeways and the River Misbourne have been threaded through a railway viaduct built in the early 1900's.