Driving is serious business and driving in flip flops has great potential for disaster. They can slip off in an instant – and in that instant someone could be killed. Wear proper driving shoes, or keep some in your vehicle.
As an instructor, I will not allow a student driver to drive in flip flops. If they come out of the house in flip flops, I will have them put on some proper shoes, or I will cancel the lesson. It is not worth the risk.
There have been numerous collisions where flip-flops were a cause and/or contributing factor. Read about them here:
Drive carefully and have a great summer.