[Joff]

I think it's normally out of desperation Rob - after pounding the tarmac for an hour or two you just want somewhere to stop, stretch your legs, have a wee and maybe grab a coffee for the remainder of the journey.

There are plenty of books and websites (or just use your satnav POI's) that detail which junctions have local services just a few minutes away but in reality it's the convenience we pay for.