Yay, Physics!

I knew a little about Doppler effect in sound and astronomy, from school, but I don't think I knew its relationship to police radar.

You may already know this, but it looks to me like the tuning fork isn't actually used when the police measure someone's driving speed. It's used to check that the radar unit is correctly calibrated, which is supposed to be done at the start and end of every shift, so there won't be any reasonable doubts about measurement accuracy in related court cases.

Not as poetic, maybe, but certainly of interest!