What Is California's Implied Consent Law?

When a California driver gets behind the wheel, they automatically consent to take a chemical test if pulled over for suspected driving under the influence (DUI). This means a driver who refuses a chemical test can face penalties including a fine and jail time, as well as a driver's license suspension for up to a year. When an officer stops a driver suspected of drunk driving, they can ask that driver to take various tests to measure their sobriety.

There are some tests that drivers can legally refuse, like field sobriety or preliminary alcohol sensor (PAS) tests, but they cannot legally refuse a breath or blood test after arrest without penalty. All drivers facing a California DUI, even those not licensed in the state, are subject to this law.

There are some tests that drivers can legally refuse, like field sobriety or preliminary alcohol sensor (PAS) tests, but they cannot legally refuse a breath or blood test after arrest without penalty. All drivers facing a California DUI, even those not licensed in the state, are subject to this law.

​Read More:​ California DUI Law: What are the Penalties & Fines? (With Chart)

California Vehicle Code Section 23612 makes it mandatory for drivers arrested for a DUI to submit to a breath or blood test to determine their blood alcohol concentration (BAC) level. A driver who refuses chemical testing is in violation of the law and can face penalties separate from the DUI charge and suffer a mandatory driver's license suspension regardless of the outcome of the DUI. This law applies to breath and blood tests after a lawful DUI arrest. A driver can, however, legally refuse to take a test before law enforcement makes an arrest.

In the 2017 U.S. Supreme Court case, ​Birchfield v. North Dakota​, the Court ruled that a defendant can refuse a blood test if officers have not obtained a warrant. Unwarranted blood draws violate the Fourth Amendment of the U.S. Constitution which protects individuals from unreasonable searches and seizures.

​Read More:​ Out-of-State DUI/DWI as a California Resident? Laws & Next Steps

Drivers face two main consequences for violating California's implied consent law: As the result of refusing a test, the state can suspend driving privileges for a year or more, and the driver faces penalties in addition to those that come with a standard DUI.

Penalties for refusal vary with the number of DUI charges:

• ​First offense:​ A one-year driver's license suspension, up to 48 hours of possible jail time and alcohol education courses for up to nine months.

• ​Second DUI charge:​ A two-year driver's license suspension and up to 96 hours of possible jail time.

• ​Third DUI charge:​ A three-year driver's license suspension and up to 10 days of possible jail time.

• ​Fourth DUI charge:​ If this charge occurs within 10 years of the other DUIs, a driver can spend an additional 18 days in jail.

When law enforcement pulls over a motorist suspected to be under the influence of alcohol, police officers investigate the driver's level of impairment and look for probable cause for arresting that driver on a DUI charge. They will observe and interview the driver and ask that they participate in a field sobriety test. Officers gauge the driver's ability to stay balanced and coordinated, and to follow instructions. A field sobriety test is not mandatory in California, and a driver can refuse one without penalty.

Prior to arrest, law enforcement may request the driver to take a test on a portable preliminary alcohol sensor (PAS) machine that officers carry with them in the field. This test is only mandatory for drivers who are under 21 or already on probation for a DUI. Other drivers can refuse to take it without penalty prior to arrest. While PAS and chemical breathalyzer tests are similar, a PAS test is far less accurate than a breath test taken in a controlled environment and is, therefore, not recognized by the court for this reason, according to The Los Angeles DUI Experts.

​Read More​: California DUI Laws: The Difference Between a "Wet Reckless" & DUI

Upon arrest, a law enforcement officer will take the driver into custody. Once at the station, that driver is given the option of taking a breath or a blood test. The law requires officers to describe both tests and to tell the driver that refusing them would lead to criminal charges and a license suspension. The driver must take one of the two tests. However, in the case of drug impairment, a blood draw is the only option, as a breath test cannot measure drug intoxication.

A chemical test refusal does not ensure that a driver won't face a DUI conviction; there is often an implication of guilt because of the refusal itself. While law enforcement won't have chemical test results to use as evidence against a driver during a DUI trial, the test refusal itself could serve as evidence, along with erratic driving, video footage of the arrest, and the arresting officer's observations.

​Read More​: Marijuana DUI in California: What to Expect & Legal Consequences

According to the California Department of Motor Vehicles, it is illegal to drive a car with a blood alcohol content over 0.08 percent or higher, but the limit is even lower if special circumstances apply. For example, for drivers under 21 and anyone already on DUI probation, the allowable BAC limit is only 0.01 percent. For those who drive a vehicle requiring a commercial driver's license, even if the driver does not possess one, and drivers for hire who have passengers in their vehicle at the time they are pulled over, the BAC limit is 0.04 percent.

A first-time DUI offense is usually a misdemeanor and includes several penalties such as three to five years on probation; three to nine months of DUI school; fines ranging from $1,500 to $2,000; a driver's license suspension of at least six months; the payment and installation of an ignition interlock device in the driver's vehicle for up to six months; and a maximum of six months in jail. An offender may also be asked to attend a victim impact program. A driver can also face indirect consequences for a DUI charge, such as higher insurance premiums, particularly if there are prior DUI convictions.

​Read More​: Boating Under the Influence in California: What You Should Know