Como se dice, "Watch out for cops" en español?
How do you say, "Watch out for cops" in Spanish?
Inglés:
Mi esposa le gusta conducir en coche demasiado rápido. Me gustaría ser capaz de advertir a ella en español.
Frases como: "Cuídate de la ley" y "Cuídate de la patrulla" y "Tienes cuidado con los Policías" no parecen dejar claro que no estoy realmente contendiendo que vi a un oficial de policía, donde "Tienes cuidado con los policías" hace. Quiero que decir se lo en una manera sucinta, y natural.
Español:
My wife likes to drive drive too fast. I would like to be able to caution her in Spanish.
Phrases like, "Cuídate de la ley" and "Cuídate de la patrulla" and "Tienes cuidado con los policías" do not seem to make it clear that I am not actually contending I saw a police officer, where "Watch out for cops" does. I want it say it succinctly, and natural.

4 Answers
There are some expressions. Here's one I've heard: "¡Trucha! ¡Hay policía! (or chotas)
In East Los Angeles you'll hear "¡Watcha las chotas! But that's awfully slangy.
Another one is : ¡Cuidado! ¡La policía! or even ¡Ten cuidado! ¡Hay policías!
"Trucha" is a little like "Jiggers!"

Just a diversion from the topic at hand:
When I was in Barranquilla, Colombia, there are many neighborhood street that have speed bumps. These are called policías. I think this is a usage limited to Colombia, but would like to know if this term is used in other countries.
In Mexico City all the traffic cops have brown uniforms, so we would say: ¡Aguas con los tamarindos!
The judicial (city) cops there are "(Los Judis) Policia judicial". These guys are not only corrupt, but they are dangerous criminals that should be avoided at all costs. The traffic cops are just looking for money.
Referring to Jubilado´s comment, speed bumps in Mexico are Topes.
When I was a lad we would call out ,R L C C ,"Run lads coppers coming".