Here we have the result of a truck/bridge interface.
Picture the scene (actually, you needn’t because here’s an actual picture). A Polish truck driver is trundling along in his Merc (yes, they make trucks) in Penyffordd (yes, there are supposed to be two “d”s. Welsh, pronounced like the th in then) in deepest Wales and encounters a bridge so clearly marked that he has no excuse for trying to squeeze his truck under it when it is manifestly too high. What a moron!
We can imagine the resulting conversation with a member of the local constabulary:
-Well, Mr Pole, what the bloody hell made you think you could get under there? Can’t you see the sign?
-Tak. Moron who put up a sign saying 4.1m. My truck is 4m exactly, is the law in Poland. Should fit easily.
-That bridge is exactly 13 feet!
-Might be, but is not 4.1m.
-Yes, a moron I’m afraid.
Moral to this sad story: if you want to convert ft to m, just ask Mr Google. He’ll get it right. 13’ is 3.96m, not 4.1m