When on duty as a bartender, how does one determine legally a patrons b.a.c. or level of intoxication?

this question is in regards to the New Mexio liqour industry, basically hw does one determine within the law, as it is unclear
You should get out of the bartending industry,it is a wicked job! YOU are giving someone a that destroys families,ruins peoples health,and kills people on the road! Do YOU not have a conscience as to what evil your doing?
If the f***er can't stand up or talk don't sell them a drink


Answers:
You can't determine a BAC. A BAC requires a breath or blood test. Intoxication though is more subjective. As a bartender it's expected that you know that signs of intoxication. Basiclly is the person's speech slured?, having trouble standing?, been served numerous alcoholic drinks?, getting iritated over minor issues?, etc. These are the type of things you must look at. There is no set point of when a person appears intoxicated. If they're indeed intoxicated but there's no outward signs you're ok serving UNLESS you know he's been served so much alcohol that even though he's not appearing intoxicated that he has to be intoxicated. (ie they don't appear intoxicated, but you've served them 5 drinks within the last hour, in that case a person must assume regardless of actions that the person is at least somewhat intoxicated)
Only a police officer can determine a person's BAC level by adminstering a breathalyzer test. However, if the person appears to be intoxicated i.e. he can't stand up, his speech is slurred, etc. he should be cut off.