The humble West Yorkshire town of Halifax may well be the creator of the most adventurous urban road scheme in the country. It's astonishing, but what was built isn't even the half of it.
The M621 has one junction where everything leaves the motorway and heads for the city, and a very bizarre junction it is too.
If you've ever been on the M62 across the Pennines, you'll know the one. It's the huge arched bridge 120ft above the road. And this is what it's like when you're standing on top of it!
Those last few miles of the M1 east of Leeds were completed in 1999. It looks for the most part like a fairly average piece of road, but one of the project's engineers describes some of the challenges that were faced.
Most bypasses go around the town they relieve. Not so the Bingley Relief Road, which ploughs through the town centre instead.
The unique and bizarre situation on the A1 Micklefield Bypass, West Yorkshire.