Callan Campbell, a recent high-school graduate, was a week away from starting classes at a local community college in August 2004 when the 1996 GMC Jimmy sport-utility vehicle she was riding in flipped over and rolled several times.

Today, she’s a quadriplegic, confined to a wheel chair and suffering regular back spasms. Ms. Campbell, now 23 years old, sued GM in a Pennsylvania court, alleging that faulty manufacturing caused the SUV’s roof to crush in and paralyze her.