Cops in Southlake, Texas just shaded the hell out of the Houston Astros for their cheating scandal in a new speeding PSA ad ... and the video is HILARIOUS!!!

The clip starts out with a cop and his radar gun looking pleasantly surprised that everyone is following the set speed limit.

You can see in the vid, car by car drives by ... and all of them are hitting 30 MPH on the dot.

But then, the camera pans over to a fireman behind a bush holding a trash can ... and that's where the 'Stros shade comes in.

The fireman -- who's wearing an Astros jersey -- is letting drivers know there's a speed trap up ahead by hitting the top of his metal receptacle ... and it's laugh out loud funny!!!

Of course, the 'Stros were just busted by the MLB earlier this month after league commish Rob Manfred said they illegally filmed opponents' signs and relayed them to batters by banging on dugout trash bins.

The cops captioned their vid, "We don't care what it takes for you to slow down and follow the speed limit. Drive astro-nomically safe today in Southlake."

BUUURNNNNN!!!