Is the rail tunnel available as an emergency tunnel for a new parallel road tunnel?While not the most economic option, the best bet for traffic would probably be to build a modern road tunnel next to the existing one, then bypass Wroxall to the east before linking up with the A3020 east of Whiteley Bank. Failing that I suppose you could make the Whitwell Road a dual carriageway.
I assume that as I haven’t heard of the rail tunnel collapsing it goes through pretty solid ground?
just checked contours - a Wroxall bypass will be heavily engineered and/or steep, particularly on the old railway side.