I'll always have a soft spot for the A1. Growing up within a couple of miles of it in Northumberland, it was the main route anywhere, north or south. Connecting the capitals of England and Scotland like the Great North Road before it, once upon a time it deserved a similarly grand title, but has been eclipsed by the motorways that now criss-cross the country (though not rural Northumberland).
The motorway experience is a largely dreary, soulless one of dull, broad carriageways and homogeneous, eye-wateringly expensive service stations (with a few exceptions: the M6 through Cumbria, the M62 between Leeds and Manchester, the M50 towards Ross-on-Wye, the Gloucester Services going northbound on the M5). By contrast, journeying along the A1 is far more interesting and in some ways feels like travelling back in time to an era of staging-post towns and idiosyncratic roadside cafes.
Peter Dench's photo series Britain on the Verge - itself a homage to a similar series taken by Paul Graham in 1981 - captures much of the unique identity of both the route itself and those who live and work by it.
(Thanks to Jen for the link.)