Reports that Mansfield was decapitated are untrue, although she suffered severe head trauma. This urban legend started with the appearance in police photographs of the crashed car with its top virtually sheared off, and what resembled a blonde-haired head tangled in the car's smashed windshield. However, the blonde object was a wig Mansfield was wearing, and possibly parts of her real hair and scalp. Her death certificate stated that the immediate cause of death was a "crushed skull with avulsion of cranium and brain". After her death, the National Highway Traffic Safety Administration recommended requiring an underride guard (a strong bar made of steel tubing) on all tractor-trailers; the trucking industry was slow to adopt this change. In America, the underride guard is sometimes known as a "Mansfield bar", or an "ICC bumper".