The Severn is noted for its extreme tidal range. This means that there are few safe crossing points for a ferry, the New Passage Ferry being the deeper channel downstream of the Dun Sand and upstream of the English Stones. This passes between New Passage Pier in Gloucestershire and Black Rock in Monmouthshire, approximately the line of the Second Severn Crossing. The other crossing in the area is upstream at the Old Passage Ferry, from Aust to Beachley, approximately the line of the earlier Severn Bridge. This crossing goes from England to England, as it is still slightly upstream of the confluence with the Wye below Chepstow, and so a crossing to here would still require traffic to cross the Wye on its way to Cardiff.
