Eyewitness News Reporter Kaitlin McCulley was able to break the driver's side window from the inside using a tool called the "resqhammer." It cost about $29 at Bering's Hardware on Bissonnet.
Check out the demonstration here:
Another tool that may be handy if the driver is completely submerged in water inside the car is a tool called "keychain Resqme tool." The device is spring-loaded, so it does not require a user to strike the window.
A company called Houston Junk Car Buyer provided a flooded car to use for the demonstration.