The U.S. government is investigating some Ford Fusion and Mercury Milan cars because the brake pedal may lose pressure, making it hard for drivers to stop the vehicle.

Three crashes were blamed on the braking issue, the National Highway Traffic Safety Administration said Tuesday. The brake pedal can go "soft" when driving on slippery or uneven surfaces. NHTSA received 141 complaints, with some reporting that their car stopped past red lights, leaving them in the middle of flowing traffic.

The investigation covers Ford Fusion and Mercury Milan cars with model years 2007 to 2009. NHTSA estimated that there are about 475,000 of those vehicles.

The maker of both , Dearborn, Michigan-based Ford Motor Co., said it will cooperate with the investigation.

The Fusion and Milan vehicles were also part of the massive recall to remove Takata air bags that could explode.