A48(M)

A48(M)

Castleton to St Mellons

The A48(M) is a little spur from junction 29 of the M4 to let traffic flow more smoothly between Cardiff and the Severn Bridges.

Routes

What's new

Imperfectly Odd: Batheaston Bypass

It has viaducts, a tunnel and plenty of controversy, but the amazing Batheaston Bypass doesn’t really work. What went wrong?

South London's lost motorways

Completing the story of London's epic Ringways, we've just published the Southern Radials, five more motorways that never saw the light of day.

To the north east!

Two new additions to our collection of Opening Booklets take us to Darlington and Middlesbrough.

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Emergency Diversion Routes

Those funny black and yellow symbols are everywhere - and they might just get you back on track one day.