My wife was driving and I was passengering on our way back from the store. As we came over an overpass, the speed limit changed sharply from 50mph to 35mph, with effect directly at the bottom of the hill that was the overpass. My wife commented that it's hard to decelerate that much on a downhill run of that distance. I suggested that she not decelerate.
Her response was that there might be a cop with a radar gun, and then came the fun with physics.
I suggested that she accelerate instead of decelerate; after all, once she achieves a certain speed, she'd get past the cop's radar gun before it could trigger. In fact, the task would be a bit simpler since the cop's radar gun's photons would have to make a round trip over the same distance my wife and I would need to cover only once.
Furthermore, having achieved that certain speed, she'd likely get abeam the cop's radar gun before she'd left the overpass hilltop. From that, any causality problems ensuing from the cop choosing to trigger his radar gun anyway would be on the cop—textbook police brutality.
As my wife put it, #photonlivesmatter.