Alcohol addiction afflicts many individuals and no doubt, is one of the main factors in many DUIs. But what about marijuana? Is marijuana also addictive? Now that recreational marijuana is legal in California, will we start seeing an increasing number of multiple driving under the influence of marijuana offenders and an increasing number of crashes caused by marijuana-influenced drivers?

According to the National Institute on Drug Abuse (NIH), a person with “marijuana use disorder” uses marijuana frequently and often experiences withdrawal symptoms if he or she stops using the drug. This disorder, according to NIH, afflicts approximately 30 percent of those who are marijuana users. Some individuals with Marijuana Use Disorder cannot stop using the drug; these individuals become addicted to marijuana. The NIH reports that approximately 9 percent of marijuana users will become addicted. In 2015, approximately 40 million people in the United States have marijuana use disorder. Extrapolating from that number, there are approximately 432,000 individuals addicted to marijuana in California. (This is a rough estimate.) Of course, this number pales in comparison to the estimates of the number of alcoholics in California— approximately 5 million—but now that the use of recreational marijuana is legal, it is reasonable to suspect that more Californians will find themselves addicted to the drug?

We have no doubt that alcohol impairs a person’s ability to drive safely, but there are conflicting studies regarding the effects of marijuana use on driving ability.  However, the potency of marijuana has been steadily strengthening over the years, foreboding the possibility of not only more addicts but increasingly dangerous effects on the ability of a high driver to drive safely.

The vehicle code, section 23152(b) makes it unlawful to drive with “0.08 percent or more, by weight, of alcohol in [a driver’s] blood.” You might immediately note that most DUIs are charged based on a breathalyzer measurement, not a blood measurement. I previously discussed how breathalyzers measure the alcohol content in a person’s blood but to complicate matters, the alcohol weight in a person’s breath must be translated into an equivalent blood weight measurement . If you continue reading section 23152(b) it states, “percent, by weight, of alcohol in a person’s blood is based upon grams of alcohol per 100 milliliters of blood or grams of alcohol per 210 liters of breath.”

These different measurements of alcohol by weight depending on whether the test was of blood or breath is known as “partition ratio variability.” The more accurate measurement of BAC is by measurement of alcohol content in the blood. Breath analysis loses some accuracy and though rigorous scientific testing, test established that the average amount of alcohol in 230 liters of breath is equivalent to what would be found in the 100 milliliters of the same subject’s blood. This may vary from person to person on either side of the scale. To allow for possible variations among individuals and to give the benefit of the doubt to the driver, the California legislature, set the conversion at 210 liters of breath to 100 milliliters of blood, or a ratio of 2,100 to one.

Before it was amended in 1990, section 23152(b) defined blood alcohol concentration (BAC) only in terms of “grams of alcohol per 100 milliliters of blood.” Because, then as now, many DUI charges were based on breathalyzer results, the breath results had to be converted using the standard 2,100 to one ratio. But because the partition ratio was not written into the statute, a common DUI defense was based on the effect of partition ratio variability factors. Following amendment of the law, the California Supreme Court held that the amended language was meant to criminalize driving with the specified blood alcohol level or the specified breath-alcohol level. In other words, the amendment did not simply provide an alternate method for calculating BAC but was meant to make it unlawful to drive with an .08 percent or more BAC as measured per 210 liters of breath.

Driving under the influence is most commonly associated with younger drivers under the influence of alcohol, but if you are a regular reader of this blog, you know that unlawful DUI includes not only driving under the influence of alcohol but also driving under the influence of drugs, both legal drugs (including prescription drugs) and illegal drugs. Driving under the influence of drugs is becoming an increasingly dangerous occurrence on our roads and highways. According to the Center for Disease Control and Prevention (CDC) drugs (legal and illegal) account for 16% of all motor vehicle crashes. The National Institute of Drug Abuse (NIDA) estimates that 11% of fatal vehicle crashes involved a driver under the influence of a drug or drugs.

With our aging population, another fact must be addressed: older adults are more likely to be taking prescription drugs that may affect their ability to drive safely. This is a sensitive topic that hasn’t received much attention. The NIDA cited a study that found more than one-quarter of drugged drivers involved in fatal crashes were over the age of 50.   As the NIDA observed: coupled with mental decline and the slowdown in the ability of an older adult’s system to process drugs, the use of prescription drugs can lead to the unintended driving under the influence by older adults.

And just because the drug is prescribed does not mean the older driver can’t be arrested for a DUI. This is especially true if the driver causes an accident or worse.

Perhaps you will not be surprised to learn that the United States has among the highest rates of death from drunk driving in the world, with 31 percent of all fatal accidents being attributed to alcohol impairment. You might be surprised to learn that our neighbor to the north, Canada, has an even higher rate at 34 percent and South Africa’s rate is even higher at 58%–that represents 25.1 deaths caused by impaired drivers for every 100,000 people in South Africa. These three countries, according to the Global Status Report on Road Safety (2015) have the three highest rates in the world of road deaths caused by impaired drivers. Australia, France, and Italy come in just below the United States at 30 percent, 29 percent, and 25 percent, respectively.

There may be a number of reasons to explain the high rate of fatalities caused by impaired drivers, including lack of public transportation options and dispersed population centers. But Russia, a country rumored to celebrate drinking and a country with a huge land mass, is reported to have only 9 percent of its road fatalities caused by drunk driving. Now you might reasonably surmise that Russia’s statistical reporting is lacking or otherwise manipulated, but the World Health Organization, which compiled this report takes into account any data manipulation or lack of reliable statistics. Germany, a country known for its robust beer drinking, matches Russia’s 9 percent rate.

Could these differences be explained by the drunk driving laws? Perhaps, but probably not by the legal BAC levels. Canada (most provinces) and the United States have a 0.08 percent BAC threshold. But the legal limit is South Africa is 0.05 percent BAC. And while Germany and Russia have a 0.05 percent BAC legal threshold, so does Australia, France and Italy, countries that have a much higher rate of deaths caused by impaired drivers. Consider that France, with a 29 percent rate of drunk driving fatalities has a 0.05 percent BAC threshold, while Great Britain, with a 16 percent rate of drunk driving fatalities has a 0.08 percent BAC limit.


Being arrested for driving under the influence doesn’t always happen when are driving a car. As I previously discussed, you can get a DUI while driving a golf cart, riding a bike, or operating a boat or jet skis. Here’s a new one: Riding a horse while under the influence.

Yes, indeed. This past weekend, a man on a white horse was arrested for riding his horse on the 91 Freeway. Riding a horse down the freeway is unlawful enough, but this knight on his white horse was suspected of being drunk, very drunk. His initial blood alcohol screening registered a .021% BAC.

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When a driver is convicted on a DUI, his or her term of probation will include a requirement to complete a DUI program. On a typical first-time conviction, the driver will be required to complete a 3- to 4-month, 30-hour program. In some instances, the court may order a shorter program of 12 hours if the offense was reduced to a “wet reckless” or for other reasons, such as a conviction on a below .08% BAC. However, if the driver’s BAC was over .19% or if there were extenuating circumstances, such as reckless driving or an accident coincident to the DUI, the court may order a 6-month, 42-hour program or even a 9-month, 56-hour program.

In straight DUI conviction, without enhancements, the 6-month and 9-month programs are generally ordered only on a second or third DUI (within ten years). A driver convicted of a third (or more) DUI within ten years will be ordered to complete an 18-month, 64-hour program or even a 30-month DUI program.

A Foothill Ranch woman faces a murder charge under Penal Code section 187(a). It is alleged that on October 1, 2016, this woman, only 24 years old at the time, “with malice aforethought” killed another human being. Why am I writing about this on a DUI blog? Well, this young woman faces murder charges because she caused the death of another after her vehicle crashed into the truck of the deceased. It is alleged that she was intoxicated when the collision occurred.

When a person causes the death of another in an accident, it is usually charged as manslaughter if the fault of the accident was due to the driver’s negligence or if the driver was violating the law. When a driver is DUI and causes a fatal injury to another, the driver may be charged under Penal Code section 191.5 for vehicular manslaughter. This is a separate offense and by definition includes gross negligence.

But when a driver causes the death of another while under the influence of alcohol or drugs and has been previously convicted of a DUI, the driver may, and probably will, be charged with second-degree murder. A DUI murder charge is no different than any other second-degree murder charge and carries of punishment of 15 years to life imprisonment in state prison. The murder charge this woman faces is called a “Watson murder,” so named following a California Supreme Court decision in 1981 (People v. Watson). The Watson court held that when a person drives under the influence, the driver acts wantonly and in disregard for human life. This rises to the level of implied malice. Without getting too technical, California law provides that anyone convicted of a DUI be advised that driving under the influence is dangerous to human life and that if the driver kills someone while driving under the influence of drugs or alcohol, he or she can be charged with murder. This is called a “Watson Admonishment” and provides a basis for the prosecution to allege that the driver had the requisite mental state of implied malice.

A while back, I wrote a piece on my criminal website blog about donkeys serving time in jail. Now, we have a dog arresting a DUI suspect…. Well, sort of.

Last week, police attempted to stop a suspected DUI driver in Orange County. The police had been alerted because they received reports that the driver had hit a trash bin. The driver made the poor decision to keep on driving, entering the 55 freeway then driving onto the 91 before exiting. At some point he stopped, but by now this had become a full-on police action, with a K-9 unit and even a SWAT team called in.

A stand-off ensued but after 4 ½ hours, it was the police dog who took down the recalcitrant DUI suspect. Reportedly, when the suspect came to a stop, surrounded by police vehicles, he made threats to harm the officers. The suspect apparently had mixed feelings as he kept opening and closing his car door. This gave the police dog an opportunity to move in. The dog took multiple punches from the suspect but just kept at him. This allowed the police to move in and taser the suspect. The suspect was arrested and taken in an ambulance where he was being treated for dog bites. The police report he was suspected of driving under the influence of drugs but did not give any more information.


It was sure to come soon. A San Francisco driver was arrested for DUI last week after he was found sleeping behind the wheel of his stalled Tesla smack dab in the middle of the Bay Bridge. The driver pleaded his innocence to the officers on the basis that his Tesla Model S was on autopilot. Nope, not so fast—at least for now. While the “self-driving” ability of the vehicle may have caused the driver to believe he could use the car as his “designated driver” or at least use that as an excuse when the cops found him, the Tesla isn’t yet ready for prime-time self-driving capabilities. For now, the self-driving cars have all the driver controls and requires an alert driver in control of the vehicle, even if it is presumably driving itself.

But this poses an interesting question that law makers will have to address in the near future when self-driving cars really are self-driving with no driver required. Yes, that is coming.


While promising trends suggest a declining number of drivers are getting behind the wheel while under the influence, statistics from this past holiday season may be cause for concern. The holiday season of 2017 saw a substantial increase in the number of drivers arrested by the CHP for driving under the influence as compared to the 2016 season. Statewide, arrests for DUI were up almost 20% over the prior year during the Thanksgiving holiday and up 30% during the Christmas holiday. The New Year’s holiday weekend continued the trend with a 22% increase in drunk driving arrests. The uptick occurred over all areas of the state; it is not attributable to only a few locales.

What explains this? It may be a one-time spike and no trend at all. Or a reasonable assumption may be that this holiday season, CHP patrol and enforcement was increased as compared to last year. While that may make sense, it is incorrect. The 2017 holidays were a Maximum Enforcement Period as were the holidays in 2016. For many years now, the CHP has been conducting Maximum Enforcement Periods (MEP) wherein more CHP officers are deployed on the roads. MEPs are conducted during the winter holiday season and warm weather holidays such as the Fourth of July and Memorial Day. During an MEP, all available officers in the state are called to duty. Their enforcement focus is on speeding, seat belt violations and, of course, driving under the influence of alcohol or drugs.