Maybe, but I don't see the point. Speaking with your hands is weird no matter what you are doing. Learning ASL signs instead of something else is that much harder, and ASL is a lot richer than either.

Of course I can't claim any ability in ASL. When taking the baby sign language classes my teacher was very insistent that to the baby what sign you use doesn't matter, but we should use ASL signs because learning any other sign isn't any easier, and this way we have a few dozen signs that are actually useful after the baby grows up. Which is the point: if you learn some signs of ASL you can communicate better than pointing. When you learn something else your are just pointing and hoping you are understood.

If the signs are just small set of cues for the most common phrases a police officer needs to convey, then why not just teach this as an ASL subset?

Did you watch the video on Cued Speech? It's not a set of signs for common phrases at all. It's simply a small set of gestures that accompany some of the hard-to-lip-read sounds, like /m/ /p/ /b/.

So if you're saying "mat" "bat" or "pat" those all look the same to a lip-reader. With the cues, you have a small gesture that is distinct for /m/ /p/ /b/.

They combine together to make a total of about a dozen gestures that can be used to differentiate between any hard-to-understand English word.

So it's not a phrase book. It just allows you to say anything you want to say and be understood a little more clearly by a lip-reader.