On interstate 5 at the Headquarters Rd. overpass.
Travelling south, it is 70 m.p.h. and there are trees on the east side of the overpass. A W.S.P. sits just behind the trees, with radar to clock southbound traffic. He can cross the overpass and speed right onto the freeway.
I got out of my ticket, (for some divine reason) but I have seen many people stopped.