Well, usually driving over one with rubber tires causes no problem. One in the air would be detectable, no?
And the requirement is not just braking action, like with a railroad crossing it is active avoidance.
https://www.pge.com/en_US/safety/electrical-safety/what-to-d...
My point is - corner cases like these tend to create "IF" statements in a "pure physics model" that is used for decision making under uncertainty. And engineering such models without "ML fad" is difficult.