Near Norfolk, VA, years ago, I saw a 12 foot, aluminum car top boat get launched into the air at 70 mph in holiday traffic, it was on a station wagon, tied to the top.
It went maybe 20-30 feet in the air, then 'stalled' like a badly made paper airplane, and hit the pavement in the middle of speeding traffic. Talk about chaos?
Ladders, sofas, and every summer I can tell it's vacation time because the amount of ice coolers, and RV airconditioning unit plastic covers multiply on the side of the road.
Life jackets, if you are near a large body of water.
Last night I saw a box truck with a built in, extendable ramp, driving around with the ramp extended.
It had just exited I-20, in pretty fast and heavy holiday weekend traffic.
I think the ramp didn't slide out until it hit the off ramp, was in when it passed me a few minutes earlier. It's probably a good 'anti-tailgating' device, but I doubt your insurance company would approve.