The A601(M) is a short link road that connects M6 junction 35 to the local road network just north of Carnforth. At first sight it looks like a short road carrying low levels of traffic both east and west from the M6, but actually it's one of the UK's more peculiar and interesting little motorways.
It started life as part of the M6 itself, and for ten years formed the northern terminus of the Lancaster bypass, which turned a sharp corner at what is now junction 35 and then ended at the roundabout with the A6. When the M6 was extended northwards in 1970 it branched off at a new junction, number 35, leaving behind a spur to the A6. For the next 17 years this was just a simple motorway spur from the M6 to the A6.
One of the main uses of junction 35 was for traffic accessing the M6 from a quarry at Over Kellet, just south-east of the spur, all of which had to pass through Carnforth. That was evidently silly when it was passing right by the motorway junction but couldn't get to it without taking a long route through a town centre. So, in 1987, the Over Kellet Link opened, an extension of the spur from M6 junction 35 eastwards, running the short distance of two hundred yards to reach the B6254. The extension connected only to motorways and so it's under motorway restrictions itself, but it is a single carriageway road, with one lane in each direction. It's the only motorway to terminate on a B-road, and does so with a Give Way sign. It's one of very few single carriageway motorways in the UK; another opened in the same year, the A6144(M), but that has since reverted to a normal A-road.
As if this didn't make the road strange enough, the spur now extended in both directions from the M6 and the Department of Transport decided that made it eligible to be given a number of its own. For reasons that have never been properly explained they called it the A601(M), a number that makes no sense whatsoever. "A601(M)" ought to be a part of the A601 under motorway restrictions, or a motorway bypass of part of the A601. But it's neither, and if you look at a map of the area surrounding Carnforth, the A601 is nowhere to be seen. In fact it's a very long way away - it forms part of the Derby Inner Ring Road, more than a hundred miles to the south east.
Between its prestigious history, its strange layout and its inexplicable number, the A601(M) can keep a road enthusiast busy all day - which is more than can be said for a driver. At just over one mile in length the whole road can be negotiated by a determined motorist in about one minute.