Those low bars on trucks? Here's the story behind them. (Aside: The 3 adults were killed. Jayne Mansfield's 3 children were riding in the back of the car. Her daughter, Mariska Hargitay, was the only child injured, a cut to her head.)
Mansfield Bar on truck
During the 1960s (june 1967), the actress Jayne Mansfield was killed in a gruesome accident when the car in which she was riding rear-ended a slow moving truck in the fog.
Her car went under the back of the truck. Accounts differ--some say she was beheaded by the impact, others that the impact scalped her, and others say that her wig was knocked off by the impact.
Whatever the details of the wreck, regulations were enacted to add a low bar at the rear of truck trailers, to prevent a car from running underneath the trailer from behind. Jayne's tragic death has left a legacy of improved safety equipment.