Impaired to the slightest degree in Arizona DUI cases

I frequently get the question of what does it take to be "impaired to the slightest degree" in Arizona DUI law. The answer to that question is not cut and dry, and is the reason that many cases go to a jury.

The prosecutor tries to use the breath or blood test to prove that the driving was impaired. However, that test is never taken concurrently with the driving. They try to use the field tests, but the tests may not show imapirment, and are also not done concurrently with driving. There are unlimited alternative reasons why somebody might not be able to stand on one leg for 30 seconds.

So why publicize Mr. Johnson's arrest without first confirming the blood test result? It gives the impression that Arizona prosecutors will proceed with the charges even if the blood test does not exceed the legal limit. While this is certainly technically true, it gives the impression that Arizona is a zero tolerance state (i.e., driving with any alcohol in your system at all is illegal).  That is not the case. In fact, juries are regularly instructed by Judges that it is NOT illegal to drink and drive.

Quoted from http://www.themoneytimes.com/news/20070624/tank_johnson_busted_for_dui_in_arizona-id-105261.html:

Tank Johnson busted for DUI in Arizona - The Money Times

Police in the Phoenix suburb did not reveal the results of the test; however they told the newspaper Johnson appeared impaired and was charged under a state "slightest degree" law allowing drivers to be arrested even if they don't exceed the state blood-alcohol level of .08 percent.

The bust is the latest brush with the law for Johnson, who has been suspended by the NFL for the first half of the 2007 season and spent 60 days in jail for a parole violation.