[DaveinGermany]

Originally Posted by westendlass

Yes, but these days they'd soon be filled by dodgy characters, druggies and weirdos. You'd need an armed guard at each end.

But this would then give Plod the chance to shine! He could take a "proceed" as in "Hi was proceeding halong the highway, when the miscreant ......... blah de blah de blah" to the said underpass & lo & behold he could apprehend all the villains & wastrels in one fell swoop! Back to the station, tea & toast & promotion to chief super!