Wrong! Wrong! Wrong! Where do you get that crap???

What is admissible varies by state, but generally in the US field sobriety tests are admissible. States may have specific requirements as to what tests are used and how they are conducted. Some states may even not admit these tests, but most do. Note that admission of evidence does not equal guilt, that's up to the jury.

You can get arrested for DUI based on any of a number of probable causes...whether you get charged/indicted and convicted is another issue.

The portable breathalyzers were NOT designed to produce a legal BAC results...but these days they are often being admitted as evidence anyway to show probable cause for the arrest and to strengthen the case. Again, it varies by state.

Bottom line, thanks to MADD, this game is heavily weighted towards the interests of the state. You are pretty much presumed guilty and have to prove otherwise (driving is a privilege, not a right). Society's natural and justifiable anger towards a few reckless and irresponsible repeat offenders has unfortunately been redirected towards responsible citizens who have a glass of wine with dinner. The reprobates can't be stopped...lack of license or insurance does not dissuade them. We need to take them out back and shoot them, but since society won't do that it takes out it's anger on anyone who drinks.

Safest thing to do is not drink and drive at all. f you must make sure you stay well below the levels which SHOULD impair you taking into account all the physiological issues (body mass, alcohol content, rest, food, passage of time). Also know the rules in YOUR state...the smell of beer on your breath could create a lot of hassles even if you are unimpaired.