Manhole cover lifted by rain, opposite Bus Stop! Now replaced.

After the torrential rain on Thursday 13 August 2015 I came across heavy triangular man hole cover that appeared to have been lifted by flash flooding. I park my car with hazard lights flashing in the middle of the road and replaced it. May be this could be logged for future reference to be checked immediately after a similar storm, or to be replaced by one of better design which would self align and close safely after such an event. Are the outflows from the drain clear and adequate?

Some years ago, I wrote off a car at night when my wheels hit a hole that should have been covered by a double triangular cover on the approach to he Gate Inn Services off the A2. i.e this is not an isolated problem.