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What is a “Per Se” DUI?

What does a DUI “per se” actually mean? “Per se” is a Latin term meaning “by and of itself.” Under California law, a blood alcohol level (BAC) of 0.08% is by and of itself considered driving under the influence. (For some drivers such as those with commerciallicenses, the per se BAC is lower under the law.) It doesn’t matter if the driver is not impaired at all (although this may be unlikely); if his or her BAC tests at 0.08% or above, that driver is – to use another Latin term–ipso facto under the influence.

California DUI law makes it unlawful to drive under the influence of any alcohol beverage (Vehicle Code section 23152(a)) AND to drive with a BAC of 0.08% (Vehicle Code section 23152(b).) Why the two distinctions? Well, under subdivision (a), a person could be arrested and charged even if his or her BAC is under 0.08% if the officer believes the driver is impaired by alcohol. Subdivision (b) is the “per se” part of the DUI law. When a person is arrested for DUI, they are almost always charged under subdivision (a) and (b). The need for a per se law is evident. Without it, drivers would be subject to the officer’s own subjective determination. The inconsistencies in arrests and convictions would pose a problem. Furthermore, having a per se law establishes a cut-off point where a driver is subject to arrest.

I’m sure you’ve seen the billboards: “Report Drunk Drivers. Call 9-1-1.” The CHP and other agencies even have tips for spotting and reporting a drunk driver. So, let’s say you see a car weaving somewhat on the road and you suspect a drunk driver. You call 9-1-1 and report the driver, your location, and the license plate number of the weaving vehicle. What happens next?

Generally, the local law enforcement agency with jurisdiction over the location will respond.  Perhaps they will observe the vehicle and determine that the driver is violating a traffic law (such as Vehicle Code section 21658, lane change violation) and effect a legal traffic stop. If the detaining officers end up finding probable causeto believe the driver is under the influence of alcohol or drugs, a legal arrest will be made.

But what if the officers locate the vehicle but it is not moving? Say the driver is parked with the engine off. Can the officers still confront the driver and potentially arrest him or her if there is reason to believe the driver is under the influence? After all, the driver is not driving, and the DUI law prohibits drivingunder the influence. Over 25 years ago, in the seminal case, Mercer v. Department of Motor Vehicles, the California Supreme Court held that “driving” under the DUI law requires evidence of observed volitional movement of the vehicle.

There is nothing new about the above headline, but the truth is, many of us don’t take it seriously enough. Before we even head out to that restaurant or bar or party, we should have a reliable and responsible designated driver assigned to get us home safely. That means the designated driver should be the one who drives everyone in our group to the event and someone who everyone trusts will remain sober—that includes no drugs. Too often, a plan is not made ahead and the person who seems the soberest will get the job of driving. This may boost the ego of the “designated driver” who thinks they can better hold their alcohol than the rest or limit their consumption, but it takes very little alcohol to affect a person’s drivingand put them at risk for a DUI. The best designated driver is the one who has not been drinking any alcoholic beverages.

Realistically, there is not always someone in the group who volunteers to be the designated driver. In that case, other plans should be put into place before heading out for the event.  For example, everyone could agree to meet a one person’s house and pitch in for a ride share or taxi to the event and back. Of course, there would also need to be a prior agreement that the group can sleep at the meeting house.  In cities that allow overnight parking, money could be saved by driving to the event but taking a rideshare or taxi back and picking up the car the next morning.

Another option may be to find someone who is willing to pick the group up when called. Maybe a parent or spouse would be willing to fill this role. But plan ahead! Make sure that person is aware that you will call for a ride; don’t expect to make a drunk 1 a.m. call asking for a pick-up.

It’s 2019 and we are on the heels of the next decade in this young millennium, a decade that promises to bring technological changes worthy of a sci-fi novel. This will likely be the decade that sees a spectacular rise in artificial intelligence, including self-driving vehicles and law enforcement that takes the film “Minority Report” out of the realm of fiction (except for the precogs). The act of drunken driving and its consequences will never be the same.

While California’s recently enacted Ignition Interlock Device (IID) lawwill require most drivers arrested for DUI to install this device, which will not allow the driver to start the vehicle if alcohol is detected, we may soon see similar alcohol detection devices installed in vehicles as a matter of course.  The “Driver Alcohol Detection System for Safety” (DADSS) research program is developing technology that will be installed in every new car sold. This technology is passive. That is, it will not require the driver to do anything (unlike the IID, which requires a driver to breathe into a device). The DADSS system will prevent a driver from driving the vehicle if the driver’s BAC is over 0.08% (or if in Utah, over 0.05%). The DADSS is a nationwide program funded by the government and the private sector, including the automotive industry.

How will the DADSS system work? Currently two technologies are being explored: a breath-based system and a touch system.

A Southern California man has posted one of the most poignant yet distressing social media feeds I have seen. In a Facebook picture, Zach Kincaid is standing over a coffin, his young child looking on. Inside the coffin is his 29-year-old wife, her unborn child in her arms. In another photo, Mr. Kincaid is holding his dead unborn daughter, who was only a month away from her anticipated birth date.

On September 9 Mr. Kincaid was speaking with his wife on her cell phone speaker as she was driving on Warren Road in Riverside County when he heard her scream, then he heard a collision. A drunk driver, pro boxing champion, Marcos Forestal-Coutin, was allegedly driving under the influence of alcohol as his speeding car veered into the wrong lane, hitting Mr. Kincaid’s wife’s vehicle head on.  In what must be one of the most egregiously arrogant statements, Forestal-Coutin claimed Mrs. Kincaid’s vehicle “appeared” in front of him and then went on to complain about the damage done to his vehicle. Forestal even livestreamed a video of the crash scene.

The social media photos are very disturbing and hopefully will impress the many thousands who have seen them. Drunken driving can kill, and these photos make that lasting impression. There is really no excuse to drive drunk. Unfortunately, a brain affected by alcohol makes poor decisions.


The DMV wields a substantial amount of power over our driving privileges. When a person is arrested for driving under the influence, his or her license to drive is immediately suspended (with a 30-day grace period until the suspension takes place) unless the driver can successfully challenge the DUI arrest in an administrative per se (APS) hearing. As I have discussed on this website, the APS hearing is a completely separatefrom the criminal matter and, in virtually all DUI cases, the suspension of the arrested driver’s license to drive takes place before the DUI is adjudicated by the criminal court.

Although APS proceedings seem to fly in the face in the face of due process since the driver has not even been convicted yet of the alleged DUI, the appellate courts have consistently held that the administrative suspension is constitutional.

In previous blog posts I discussed driving under the influence of marijuana (cannabis) and the difficulties provingthat a driver was under the influence at the time he or she was driving. The active ingredient in cannabis, THC, stays in a person’s system long after the effect wears offmaking it difficult to prove that a driver was under the influence at the time of driving. And, unlike alcohol, a driver under the influence of marijuana does not always display the obvious symptoms.  Despite these difficulties in proving the offense, drivers are being charged and convicted of driving under the influence of cannabis and in recent years, there have been increasing numbers of vehicular manslaughter while under the influence of marijuana convictions (Penal Code 191.5(a).)

Recently a 24-year-old man was charged in Kern County jury of vehicular manslaughter with gross negligence after swerving his car and hitting a teacher who was seven months pregnant, killing both the woman and her unborn child. (The manslaughter charge only attached to the woman due to a “loophole” in California law which may prosecute the murder of a fetus but does not define a fetus as a victim under the manslaughter laws.) The prosecutor alleged that the driver was under the influence of marijuana at the time of the crash. Under California law, if a driver kills another person while driving under the influence, he or she may be charged with grossly negligent manslaughter.  The jury found the young man guilty but convicted him on a lesser charge of negligent vehicular manslaughter rather than with gross negligence.

In San Diego County, a 27-year-old man made a U-turn on the freeway going the wrong way and crashed head on into a motorcyclist, also 27 years old. The crash killed the motorcyclist. It was alleged that the driver was high on marijuana at the time of the crash. The driver was never given a field sobriety tests but laboratory tests were conducted on the driver at the hospital which showed “a higher level of marijuana than they normally see,” according the district attorney prosecuting the case. The driver was convicted by a jury of gross vehicular manslaughter and sentenced by the court to six years in prison. While the driver’s behavior (making a U-turn on a freeway going the wrong way for three miles) certainly suggests he was under the influence of something, apparently the only substance present in his system was the THC. It is hard to imagine that cannabis would cause such dangerous driving.After trial, the prosecutor stated that the toxicologist could not definitively say that the driver’s conduct was attributable to the influence of marijuana.


A driver can be arrested for driving under the influence even if the driver tests under the legal threshold of 0.08% blood alcohol content (BAC) or even a 0.00% BAC.  If the arresting officer has probable causeto believe that the driver’s ability to drive is impairedby any substance— be it alcohol, legal or medically prescribed cannabis, or any prescription drug (whether legally prescribed or not)—there are grounds for the arrest . When a driver tests over the per se limit of 0.08% BAC,  probable cause is presumed, but how does the officer determine that the driver’s ability to drive was impaired  when there is no obvious  symptom or immediate chemical test to establish probable cause?

It may boil down to the subjective evaluation of the officer.  In such cases, the prosecution will have the burden to prove the probable cause. Because this is often a subjective evaluation, an experienced DUI defense attorney may be able to get the charge dismissed.

According to the European Transport Safety Council, the European Union populous consumes more alcohol than any other region of the world. It is estimated that around 25% of all traffic fatalities in the EU are alcohol related.  This is actually lower than the estimated percentage of drunk driving related fatal accidents in North America, but the statistical difference may be explained by the fact that North America sees far more people driving longer distances than in Europe where public transportation abounds, where many people don’t even have a car, and if they do, their typical driving trips are generally cover far less distance than a driving trip on this continent.

Even so, drunk driving is an issue in Europe, just as it is here. And as on this side of the pond, attitudes towards drunk driving and stricter laws and enforcement have had an effect. Road deaths attributed to drunk driving have been on the decline in Europe, but that hasn’t save the thousands of lives that are lost each year in Europe after a drunk driving collision.

The European Transport Safety Council issued a report this year titled “Progress in Reducing Drink Driving in Europe.”  (Drink driving being what we call drunk, or drunken, driving in this country.) The report is interesting for what it tells us about reducing drunk driving country by country.

The California Department of Insurance just issued an advisory in preparation for heightened DUI enforcement over the July 4th holiday period. Noting that over half of vehicle fatalities involved multiple substances, including cannabis.  The CHP reports that there has been a 28 percent increase over the decade of fatalities involving some sort of drug, including prescribed drugs.

In response to this uptrend, the Department of Insurance is sponsoring demonstrations where young drivers put on a suit that simulates being under the influence of marijuana and alcohol. The suited-up drivers then drive on a controlled course. The opportunity to suit up will also be offered to reporters, no doubt with the hope that their experience will be filmed and reported on in the local media.

The vehicles that the suited-up drivers will operate will also be equipped with GoPro cameras. The footage captured will be made available to the media.   Also on hand for the demonstrations will be law enforcement representatives to discuss the effects of drunk or drugged driving.