latetonight:
In Europe 550 m vis is standard for a cat 1 approach. In US it is 1/4 mile!
In the U.S. full CAT I (ALS and HIRLs) is 1/2 mile.
If the runway is equipped with RVR the standard is 2400, but RVR 1800 if the runway has TDZ and CL lights.
Then, there are special authorizations based on HUD, etc. And, such special authorizations can bring the DA down from 200 to 150.