And which county has the worst?
Best I’d go for Northamptonshire.
Worst is a toughie though as our road network has deteriorated rapidly over the last 5 years across the board, but i’ll go for Gloucestershire.
Depends what qualities are used to decide: here are a few at first thought.
Density of traffic and frequency of hold-ups
Sensible signage and junction layout
Surface quality (number of potholes/badly re-instated excavations for gas/water etc.)
Provision of laybys/service areas (and quality of them!)
As a personal choice, I prefer routes through open country, rather than built up areas.
Durham, hardly any speed cameras 
London.
andrewv8:
Durham, hardly any speed cameras
And Northumberland given the size of it, although being a North East lad, I am not biased in any way.
Ken.
Quinny:
andrewv8:
Durham, hardly any speed camerasAnd Northumberland given the size of it, although being a North East lad, I am not biased in any way.
Ken.
Aye, Me too. Might live in Burton upon trent now but I was born & bred in County Durham.
Leicestershire la la la 
tango boy:
Leicestershire la la la
+1 
Worst Kent, I always notice the difference when crossing the border into East Sussex.
some crackin roads in wales
commonrail:
some crackin roads in wales
Not just the roads, the quality of the surface, a perfect example the A465 from Abergavenny to Hereford before you cross the border it’s like a billiard table cross over the river and it all goes to ■■■■■■
tango boy:
Leicestershire la la la
Truly shocking in Leicester reminds me of rural Spain without the sun.
We seemed to have reached an agreement Wales has the best roads.
mike68:
We seemed to have reached an agreement Wales has the best roads.
Wales?
Rather Tracks then Roads 
mike68:
commonrail:
some crackin roads in walesNot just the roads, the quality of the surface, a perfect example the A465 from Abergavenny to Hereford before you cross the border it’s like a billiard table cross over the river and it all goes to [zb].
Agreed.
Scotland has breathtaking views,but the road surface does’nt compare.
Wales roads, certainly in the mid to North area are sublime. I did a 200 mile weekend trip in the Landrover a few weekends ago and even up in the mountains the roads are all freshly surfaced and clearly marked. We did lots of off roading and the off road parts were like the A roads down here…
Gloucestershire as a whole is shocking, glad I have a Land Rover, I need it just to navigate out of my road to work and avoid all the crevices.
Best: Orange County, California
Worst: Greater Manchester