Mersea Island is off the Essex coast. There's a road that connects it to the mainland, which floods at high tide. People seem to think that they can get their cars across. Then they need rescuing.

http://www.bbc.co.uk/news/uk-england-norfolk-38030290

I've seen this myself when I've been there. You can't get across in a regular car, and it means the coastguard or RNLI get called out. You best bet is to sit it out. it's sea water, so it won't do your car any good at all driving through it.