[kube-system]

The vast majority of road intersections do not have traffic lights. This is because they are expensive. People die every day at intersections without traffic lights. The money to put up the lights just doesn’t exist. A basic 4 way stop is about a quarter million to put in traffic lights. And even at that price you do not get lights with high availability features.

[landemva]

This speaks to the need to implement systems with inherent safety. Traffic circles for cars.

I don't know what the corresponding term would be for taxiways, though I expect the reply here will be spelled 'not practical'.

[kube-system]

If you limited a design to traffic circles for taxiways, it wouldn’t be possible to cross any runways. Because planes can’t go around turns in the middle of their takeoff or landing. But if you wanted to prohibit any crossing of runways you could also just not have taxiways mid-runway. Probably not the most practical solution.

[thombat]

It would certainly be rate-limiting if every landing plane had to roll to the very end of the runway before turning off on "the taxiway". In principle this could be reduced by having planes with shorter rollouts leave the glideslope and continue level for some predetermined distance before touching down but that's got a bunch of new hazards even without adding any interesting wind.

[dmurray]

Yes, it's impractical to have a roundabout in the middle of a runway which an airliner must negotiate during its takeoff roll.

[thombat]

Given how the passengers squeak with moderate turbulence, imagine how they'll take high-speed veering during takeoff? But of course a roundabout only works because all vehicles approaching are preparing to come to a complete stop if another vehicle will intrude upon their path, which can never be compatible with "accelerate steadily to racing car speed"