Paul Van Alfen was exiting Interstate 80 in northwestern Utah last November when he lost control of his vehicle. The 2008 Toyota Camry lurched suddenly, and Van Alfen slammed on the brakes. But the car kept accelerating and crashed into a wall opposite the exit ramp. Van Alfen died at the scene. His wife and son were injured. A fourth passenger in the vehicle died at a hospital the next day.

The survivors and the family members of the victims filed a lawsuit on May 13, alleging that Toyota Motor Corp. failed to address a systemic and long-standing defect that caused its vehicles, including Van Alfen’s, to suddenly accelerate without warning. “It’s pretty serious,” said Mark Robinson, one of the lawyers who brought the case. “There are witnesses who say he tried to put the brakes on and the vehicle didn’t stop.”