A bridge spanning the Mississippi River collapsed Wednesday, sending dozens of vehicles plummeting 60 feet into the river below. How do you escape from a sinking car?
First, roll down the windows. If the windows are still above the waterline, just climb out. But if the car is sinking fast, wait for the interior to fill with water—you won't be able to open the door until there's enough water inside the car to equalize the pressure on the outside. Opening the windows helps the water flow in faster, which gives you a better chance of escaping before your car sinks too deep. Survival experts recommend keeping your seatbelt on until the last possible second. Otherwise, the rush of water could disorient and possibly injure you. Plus, it gives you extra leverage to open the door when it's time to escape. If for some reason you can't open the windows or doors, try kicking out the windshield or smashing a side window as a last resort. (You can buy emergency LifeHammers for just this purpose.)
Try not to panic. Easier said than done, of course—the impact of the water or an airbag probably will stun you. But it's hard to hold your breath if your heart is racing and carbon dioxide builds up in your blood too quickly. Survival Systems USA, a firm that trains soldiers in emergency escape techniques, 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.
When it comes to water exits, some cars are better than others. Lighter cars generally float longer, so you'd be better off in a Corolla than a Suburban. Even though an SUV has more space inside and therefore more air, its 6,000 pounds will pull it down faster.
An old Volkswagen ad campaign bragged about how a Beetle could float, but even the most buoyant cars won't stay above water longer than a minute or two. Float time also varies depending on how the car enters the water—e.g., an upside-down impact could break the windows—and how tight the seal is on the doors. (Besides kicking tires, car buyers will often slam doors to test the seal. A good seal will produce a nice, crisp thwack.)
You're also better off with a car that has manual locks and windows instead of automatic ones. A car's electronics are likely to fail soon after it goes underwater, once its "brain boxes"—small electronic modules that control the car's functions—get wet. (These devices are often sealed against moisture, but never waterproof.) Same goes for what's under the hood: Modern cars with electronic engine controls stop working when they get wet. (That's why some cars can get stranded in the middle of deep puddles.) But if you want to be really safe, you might want to get a convertible.
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Explainer thanks Richard Martin of Survival Systems USA and J.A. "Doc" Watson.