There is a DUI Necessity Defense making driving under the influence legal if there is a "Necessity" to drive under the circumstances to prevent significant bodily injury or evil to youself or others. It is a valid defense to Driving Under the Influence and related sections and many other charges. This defense must be looked at against the requirements of the Jury Instructions which define the "Necessity Defense".
Military diversion for DUI cases was ruled on by 2 different appellate courts in California, each with a different opinion. The issue has been whether or not military diversion per California Penal Code (PC) 1001.80 applies to DUI cases in California. PC 1001.80 was enacted by the legislature, took effect in January 1, 2015 and authorized individuals who are currently or had been in the US military a diversion for a misdemeanor resulting in dismissal rather than a criminal conviction.
DUI jury instructions define for the jury the specific issues they have to decide beyond a reasonable doubt in order to convict someone. There are often a number of instructions read to the Jury at the conclusion of the case depending on the evidence presented, the specific charges and allegations an individual is facing and evidence presented by the District Attorney and the Defense.
A drug DUI in North San Diego County is treated similarly to an alcohol DUI. Once someone is pulled over and the officer notices some impairment, if there is no alcohol in a breath test or there are other indications or statements concerning recent drug use, then the officer will want to take a blood test for drug analysis by the crime lab. If you do not consent to a blood test, the officer should get a warrant for the blood draw absent any exigent circumstance. The problem with refusing is the loss of license for a year for the refusal regardless whether there is alcohol or drugs in your system.