Blood-alcohol over 0.15%

Effective January 1, 2006, VC § 23578 provides for sentence enhancement when the accused submitted to a chemical test, which resulted in a BAC reading of 0.15% or higher:
In addition to any other provision of this code, if a person is convicted of a violation of § 23152 or 23153, the court shall consider a concentration of alcohol in the person’s blood of 0.15 percent or more, by weight, or the refusal of the person to take a chemical test, as a special factor that may justify enhancing the penalties in sentencing, in determining whether to grant probation, and, if probation is granted, in determining additional or enhanced terms and conditions of probation. No specific punishment is referenced in the code.

Blood-alcohol over 0.20%

If you submitted to a blood, breath, or urine test resulting in a reading of 0.20% or higher, the sentencing judge may use this fact to enhance the penalty.
Prior to 2006, VC § 23206.1 provided:
In addition to any other provision of this code, if any person is convicted of a violation of Section 23152 or 23153, the court shall consider a concentration of alcohol in the person’s blood of 0.20 percent or more, by weight, or the refusal of the person to take a chemical test as a special factor which may justify enhancing the penalties in sentencing, in determining whether to grant probation, and, if probation is granted, in determining additional or enhanced terms and conditions of probation.
Unlike most of the enhancements mentioned previously, the 0.20% provision did not previously impose a specific additional sentence to be imposed. The statute simply directed the judge to consider this evidence as a “special factor” which “may justify enhancing the penalties,” denying probation, or adding conditions of probation. Many jurisdictions commonly imposed a sliding scale for imposition of a drinking/driving program, varying by the blood-alcohol concentration. Thus, for example, if the defendant’s BAC was 0.14% or lower, he was ordered to attend an AB-541 program for three months; if the reading was 0.15% to 0.19%, a six-month program was imposed, and those with test results of 0.20% or higher were required to attend a nine-month school.
However, the 0.15% enhancement is now the only provision not to impose a specific additional sentence, as those convicted of driving with a BAC of 0.20% or higher are now required to complete at least a nine-month program.
Effective January 1, 2006, VC § 23538, subd. (b)(2) provides:
The court shall refer a first offender whose blood-alcohol concentration was 0.20 percent or more, by weight, or who refused to take a chemical test, to participate for at least nine months or longer, as ordered by the court, in a licensed program that consists of at least 60 hours of program activities, including those education, group counseling, and individual interview sessions described in Chapter 9 (commencing with Section 11836) of Part 2 of Division 10.5 of the Health and Safety Code.