Factual error: When the Bronco is underwater at the end of the movie, Claire's hands are tied to the steering wheel. Doug rips the steering wheel off. Anyone who has worked on cars knows you need a puller to get a steering wheel off, you can't just rip it by hand.
Factual error: In the Hummer scene, the signs that read "I-310 South, Bayou Bouef" and "U.S. 90 East, Bayou Bouef" in reality read "I-10 West, Baton Rouge" and "U.S. 90 East, Claiborne Ave".
Factual error: When Denzel Washington wakes up in the hospital he unplugs the cables attached to the heart monitor. By doing this he shuts down the monitor. Actually those monitors go into yellow alert by disconnecting the heartbeat sensors. They can be configured to do nothing at all by disconnecting but they will never shutdown this way.
Factual error: Near the end of the movie, the truck is launched into the Mississippi River, which has essentially zero visibility at the shallowest of depths at all times; thus the nickname "Big Muddy". In the movie, the river is crystal clear, even several feet down.
Factual error: The stolen ambulance had windows on both the driver and passenger sides of the patient compartment. Ambulances don't have windows on the driver's side, and rarely have them on the passenger side, since these walls are used for cabinets.
Factual error: When giving her phone number to the ATF, Claire says 877-504-****, She meant to say 504-877-**** because 504 is the New Orleans area code. Even though 877 is a legitimate are code, it's used for free calls and why would Claire have an 877 area code at her residence? Considering the exchange was 504, she probably just jumbled the phone # that should've been 504-877-****. The same phone area code Agent Carlin leaves on Claire's answering machine.
Suggested correction: The number is an easter egg and if you look it up, it's a number reserved by ABC/Disney specifically for TV and films: 877-504-8423.