Unlike Hedy Lamarr, who actually patented a “secret communication system” during WWII (though the idea wasn't ultimately tweaked and used until the 1960s), Jayne Mansfield didn’t design the tractor-trailer—but her death forced safety experts to rethink the potential road hazards these massive vehicles could cause.

Mansfield was one of the most visible starlets of the 1950s and ‘60s and was constantly compared to Marilyn Monroe for both her platinum blonde hair and her famous physical assets.

On June 29, 1967, Mansfield, her lawyer, her driver, and three of her five children were driving from an appearance in Biloxi, Mississippi, to New Orleans for a TV interview early in the morning. It was just before 2:30 a.m. when her car came up on a tractor-trailer too fast, not seeing it because of anti-mosquito fog clouding the highway. The small car didn’t just rear-end the tractor-trailer—it went completely underneath it, shearing the top of the car off, and killing the vehicle's three adult passengers almost instantly.

Amazingly, the three children in the backseat survived with minor injuries. One of them went on to follow in her mother’s footsteps—you might know her as Law & Order: SVU’s Detective Olivia Benson, a.k.a. Mariska Hargitay (who still has a scar from the crash, which happened when she was just three years old).

Shortly thereafter, the National Highway Traffic Safety Administration made it mandatory for all semi truck trailers to be fitted with under-ride bars, also called DOT bars or "Mansfield bars." The steel bar hangs from back of the cargo area and is designed to stop a car before it rolls underneath the trailer.

This story originally ran in 2011.