What do police use to catch speeders?

The ones ive used have a maximum on the dial that reads "100+ yds" meaning its subject to a few things but i know of lasers being able to tag cars well over 150 yds accurately (most departments do use lasers BTW, my dinky little department uses radar because we are a campus police)

The range of a radar reading depends on the power of the gun, and the reflective surface area of the traget, as well as the shape of the target.

Angled surfaces, relfect less microwave energy back at the gun than perpendicular surfaces.

Smaller objects will also reflect back less microwave energy.

The range of a police radar gun is highly dependant upon the size of the vehicle, so the range at which you could be radared would be drastically different if you were on a motorcycle, compared to a large deisel truck.

Readings from 2000+ feet are not unheard of, thoughin almost all cases they arnt admissable in court so they couldnt use a reading form that distance to say you were speeding.

100 + yards if there good ones

Buy a Toyota and find out. :D