I'm curious as to what the crash safety features in a flying car would even be. Emergency balloons? Parachutes? A collision at flying speeds is going to be bad for the riders, but the sudden stop after the resulting long fall will likely prove far more fatal.
How do you design for that? It seems the general trend in Aviation is that you don't; if you're falling that rapidly, things have gone so far south that you're just considered dead on arrival. (Best to get out of the plane quickly, and activate your parachute.) But I'm no pilot; I'd love some more experienced input on this. I think the idea of flying cars is ridiculously silly for the safety problems alone.
No one designs for mid-air collisions.
Mid-air collisions are almost vanishingly rare outside of the airport traffic pattern. If flying cars became popular, they would increase, but still, it's a very, very large sky.
Cirrus (and some homebuilts) have the BRS airframe parachute system. Quick checking the Cirrus record, it seems like 3 Cirri have had mid-air collisions; in 2 of those, the occupants were saved by the BRS system; in the other, all aboard the Cirrus perished.
Aircraft crashworthiness is predicated on surviving an under-control arrival with terra firma, possibly after an engine failure. That is the source of the restriction on stall speed in the landing configuration of single-engine airplanes of 61 knots (~70 mph) or in the case of LSAs 45 knots (~52 mph). Shoulder belts are one of the most important factors for survivable aircraft accidents. There's a somewhat common saying, "Aircraft that crash upright and under control have survivors on board." The vast majority of aircraft crashes have zero fatalities (typically over 80% are non-fatal).
My dad (AF flight instructor) relates that crew in a fighter often release the shoulder harness but keep the lap belt on while taxiing. One day, a fighter with a tandem crew taxied off the runway into the mud, the nosegear stuck in the mud, and the jet dug its nose into the ground.
The guy in front, who had left his shoulder harness on, walked away. The guy in back didn't, and had his brains splashed all over the instrument panel.
After seeing that, my dad never took off his shoulder harness until the airplane was parked and the engines were shut down.
How are you assuming flying cars would work? Because I picture flows of "air traffic" along prescribed "air roads", not arbitrary free three-dimensional movement. Which, obviously, allows for (at the very least) rear-ending.
To oversimplify hugely, if you look at commercial aviation, that's near enough how it works. But it's all controlled by ATC who give you a height, direction and maintain separation. A flight plan must have been filed before the flight so ATC know your route. So take all that huge sky and force the planes down little corridors :)
Flying cars are much more likely to be VFR flights in uncontrolled airspace. Go where you like, tell no one, don't hit anyone, stay out of controlled airspace and in sight of ground, responsibility rests with pilot.
I'd be very surprised to see enough flying cars around to reach high enough density to raise risk noticeably outside already high traffic areas.
How do you design for that? It seems the general trend in Aviation is that you don't; if you're falling that rapidly, things have gone so far south that you're just considered dead on arrival. (Best to get out of the plane quickly, and activate your parachute.) But I'm no pilot; I'd love some more experienced input on this. I think the idea of flying cars is ridiculously silly for the safety problems alone.