You're Safe in a Stopped Car

You stop for a school bus and get rear ended by a bum. Or, you've pulled over to the side of the highway for a good reason and, next thing you know, you get hit by a distracted driver. Everyday occurrences, not anymore. Seen those thick waist-high metallinc poles they use to protect some structures - in parking garages and gas stations? Here's the twist - they'll be scattered all over the place and controllable - they'll normally stay underground, except when it's essential to get them out. Say you're in your car and there's an impending collision on account of a bum heading for you. Sensors detect the approaching villian and a computer raises as many poles as required/possible to thwart the villian - he'll have a terrific collision - which he would have anyway - but you'll be as protected as much as possible.