Another daft sign

I CANNOT resist sharing the latest incomprehensible sign from CaRT's Department of Silly Notices, writes David Hymers.

This one appears at the first lift bridge on the Llangollen Canal, just before Wrenbury. Yes, it is a low bridge, but this is fairly obvious and even a canoeist (probably) would not try to get under it.

If what they mean is that the bridge in the up position might foul your boat, then why not say so? In any case, it is not a threat in that way, there is no sign for boats coming from the Welsh direction and no such sign appears at any of the other lift bridges, at least as far as Ellesmere.

So what mental process caused the sign to be erected, no doubt at significant expense?