A retro ride on the M48, filmed back in 2009, taking in the Severn Bridge (which doesn't touch Wales), the Wye Bridge (which actually does cross into Wales), and the now-removed westbound only tolls. If you can believe it they were cash only when this was filmed, and I chose to sit behind a caravan to pay when there was an empty lane to the right.
Map extract from OS Opendata 1:250,000 Scale Colour Raster under the Open Government Licence 3.0.