Remember the motorized retracting radio antenna option that some cars had back in the 70's/80's? Well I want something like that, only on the driver's side of the car. And I want it to be a pipe with an elbow that can be raised like a submarine periscope. Only instead of lenses, I want it to be hollow. And instead of being an air intake like those snorkels on Hummers and Jeeps, I want it to be connected to the exhaust system and have a valve that can be actuated from a control in the cabin.
This way when I'm stopped at a traffic light, and next to me on my left is a big-ass truck jacked up off the ground with its "tailpipe" aimed right at my driver side window, smogging me out, I can flip a switch and return the favor and redirect my noxious emissions into one of *his* windows. (Or even better, a rubber hose that can be extended out from the car sideways to slip over the offender's tail^Wsidepipe, and reroute their own exhaust back at them!)
p.s. Speaking of automotive "why is this shit even legal?", how come motorcycles don't have to have mufflers? I have to notice one coming up on me and quick stick a finger in the appropriate ear so that blood doesn't shoot out of it when the guy roars by. I can be just about to fall asleep and one will go by on the main street down the block from me.
So I guess I also could use a 125 dB loudspeaker, which is just the threshold of pain but no real damage, on a turret on the car's roof, that automatically tracks an above-average loud noisemaking object, and when in range delivers a massive sound pulse of this.