(Ba-dum.)

I thought those two-foot-wide white marks were only used for aircraft timing. Where they're used here, they are always on stretches of road that have a "speed checked by aircraft" sign.

Aircraft traps are the easiest to spot, you can see them from miles away. The plane will be flying low, parallel to the highway. You'd have to be not paying any attention to the sky at all to get nailed by an airplane trap.