Crossed it several times.
How long does it take? 2 minutes at the most. And you can see all the way. So he MUST have driven onto it while it was already under water?
I can only assume he thought "it can't be that deep" and carried on?
The ignorance, or lack of interest, of townspeople about maritime life can be surprising. A friend was approached by a family on the beach at Clacton who had been forced to move their clobber up the beach a couple of times as the tide came in. The question was "Does it always do this?".
My boss needed to inspect some building work on a half tide swimming pool at Canvey Island. I told him that low water would be at 14.35, so off he went. He was soon back because his sat nav told him he wouldn't get there until 14.45 so he thought the tide would be in.
He was from South London, but otherwise a nice bloke☺
To be fair, tidal ranges here in Sarf London aren't that great, unless you're talking about the rising tide of crime.