Which type of collision is most serious when the occupant is not restrained because it has the potential for multiple impacts? Scene Size-Up Which type of collision is most serious when the occupant is not restrained because it has the potential for multiple impacts? A. side impact B. rear-end impact C. head-on, up-and-over D. roll-over Answer: D Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+