Blackpool needs a direct motorway connection to the M6 and the wider world, and the M55 is here to do the job.
It begins to the north of Preston and runs to the outskirts of Blackpool where traffic is dispersed onto a number of smaller approach roads. Its official name is the Preston Northern Bypass.
During the summer, it's often thick with traffic, and accounts for about half of the traffic load of the M6 around Preston. In winter months it tends to be noticeably quieter. Even so, Blackpool and Preston are large urban centres in their own right, and the motorway remains reasonably well used all through the year.
There's no junction 2 on the M55, which was reserved for the Preston Western Bypass. This road was first proposed in the 1950s, and when the M6 was first built it was supposed to be one side of a complete box around the city. The plan reappeared in the 1980s, and eventually was cancelled for good. Its fate was sealed when the M6 Preston Bypass was widened to dual four-lanes instead.
The original plan was to extend the M65 to join the M55 at J2, and construct an M59 from the missing junction on the M58 to the south-west of Preston. A western distributor road is now being built, which will connect to a new junction 2, but it won't cross the Ribble - it's just there to open up land for new housing developments, and will go no further than the A583.
The M55 is perhaps the candidate for most unassuming bit of road to be a crucial part of British motoring history. The section of motorway from the M6 to M55 junction 1 was built as the northernmost part of the Preston Bypass, meaning that it was once Britain's first motorway.