Do you wait until the car has filled up with water so the car is pressurized and you can escape more easily? This is a common answer, but could get you killed. Many die because they have received the wrong information on how to escape a sinking vehicle. Breathing from a bubble of trapped air, kicking out a window or waiting until the car touched bottom all yields a less than 10 percent survival rate.
Here are the Facts:
Stay Calm: When an emergency arises and no plan is in place, things get tricky pretty fast. Stress or anxiety, especially after an unexpected event, leads to a short term imbalance of neurotransmitters, such as serotonin and norepinephrine, and inevitably leads to physical and emotional reactions to stress such as disorientation, increased breathing, panic and heart palpitations. Knowing how to curb these natural reactions can reduce the emotional and physical reactions.
Have a Plan: In a one minute period, a car will completely fill with water. Having a plan in place is the best way to improve your chances of survival and those with you. If the water is filling the car, quickly talk to your occupants and let them know what needs to happen. It is paramount that you keep as calm as possible because you have very little time to act. Survival Systems USA, has found that it takes about 20 seconds to escape through the door of a submerged car. A calm, relaxed person can hold their breath for 30 to 45 seconds underwater. So, if your pulse is pounding, you don't have much room for error.