A nifty pair of Havaianas can set a summer outfit off nicely and they are good for lounging around the house in at any time of year. But if you are thinking of driving in flip flops please don’t do it! Flip-flops are not a sensible choice of driving shoe. They are flexible and can very easily bend and get wedged under your pedals causing you to loose control of your car.
While not illegal to drive in Flip Flops if you were involved in an accident the police would likely take a very dim view of you driving in them as they know it can prevent you from controlling your car correctly. So just don’t do it under any circumstances. Take them off, put them in the passenger foot-well and drive barefoot instead. It is much safer to drive barefoot than to drive in flip flops.