Going to wade in here for just a short time. I spent some time in the DUI squad when on the department.
First thing is that most (if not all, I simply do not know) state statutes regarding DUI have an impairment clause. Impairment does not hinge on a BAC of .08, .10 or even .38% Blood / alcohol content (BAC). Impairment simply notes that if your performance is impaired you are not fit to drive. For some folks, that can be as low as .02% due to genetics and tolerance. A person drinking for the first time has a lower tolerance than an alcoholic.
A BAC level of .08, .10 or whatever is a LEGAL finding written into the code. This legal finding states that there is a
PRESUMPTION of intoxication if your BAC is that level. In other words you are considered to be "legally drunk", which is in fact illegal when driving.
A lower BAC does NOT mean you are not impaired by that level of alcohol and hence you can still be driving "drunk"
UNDER .08%.
In Arizona, if you are impaired to the
SLIGHTEST DEGREE then you are guilty of driving while impaired (drunk driving if you will) and desreve to lose your driving priveledges and have other sundry sentences levied on you.
Field sobriety tests are used to determine if you are impaired. A breathalyzer or other test is used to determine how much alcohol you have in your system. The impairment also applies to drug usage. This leads to the change in the title of the charge to be driving while under the influence of intoxicating liquor OR drugs. There is no diferentiation between legal or illegal drugs. If you are impaired you should not be driving. PERIOD.
Several medical factors also determine how impaired a person is at any given time. Factors such as fatigue, combination of medications, genetics, food intake, tolerance etc. all combine for each individual to determine a certain point where they would be impaired. These can change a persons tollerance to a couple drinks (the usual amount admitted to) to be very devastating to their ability to drive.
That sad fact of life, is that a significant portion of collisions ( I refuse to call them accidents) are due to impaired drivers. An even sadder fact is that they often kill someone besides themselves while impaired. It wouldn't e so bad if it was just the damn drunk that got injured or killed.
You can believe what you want but you had better believe that there are TONS of drunk drivers out there every day. It may come to pass that you might meet one of them and you just might not be able to do a damn thing about it either.
Yes I have been hit by a drunk driver. Fortunately I was lucky and got out of it with a wrecked motorcycle (with less than 500 miles on it) and some bruises.
There ain't no such thing as a "safe" driving drunk or drugged person.