Your head is supported and protected by a car's headrest — you're less likely to sustain the neck injury known as whiplash with a well-designed headrest. Headrests or head restraints have been required in cars since the late 1960's, when they became a mandatory safety feature in new automobiles. While the driver rarely actually rests her head, her front seat passenger might tip his seat back on a long trip to get full use of his headrest.