Category Archives: Field Evidence

Finger-to-Nose Testing Explained

When you are stopped for driving under the influence, an officer may have you perform one or more field sobriety tests. The purpose of these tests is to determine whether you are under the influence of drugs or alcohol. The National Highway Traffic Safety Administration (NHTSA) has approved and standardized three field sobriety tests for use during DUI investigations:

  • HGN (horizontal gaze nystagmus) test
  • Walk and turn test
  • One-leg stand test

Many police officers use the “finger-to-nose” test during DUI investigations. However, this test is an unofficial field sobriety test that the NHTSA does not approve. As such, several issues can arise when a police officer uses the finger-to-nose test as part of a DUI investigation. 

What is the Finger-to-Nose Test?

A police officer instructs you to close your eyes and slightly tilt your head backward. Then, with your index finger, you touch the tip of your nose. The police officer has you repeat the process three times with each hand. Before each attempt, the police officer informs you which hand to use to touch the tip of your nose.

During the finger-to-nose test, a police officer observes you for signs of impairment. Specifically, the officer observes:

  • Your ability to follow instructions during the test
  • The direction and amount your body sways during the test
  • Whether you have body, leg, or eyelid tremors
  • Your depth perception and muscle tone
  • Unusual sounds or statements you make during the test
  • Whether you can touch your nose with your index finger or other parts of your face

Because the finger-to-nose test is not a standardized field sobriety test, police officers are not required to use specific procedures to instruct the person how to perform the test. Likewise, officers are not required to perform the test under specific conditions.

Therefore, the test can produce wildly inaccurate results because of a police officer’s subjective view of the suspect’s performance. A DUI defense lawyer may attack the validity and results of the finger-to-nose test on many points.

Field Sobriety Tests Used During a DUI Investigation

The three NHTSA standardized three field sobriety tests used during DUI investigations. Several scientific studies validate the correlation between performance during these tests and DUI impairment through statistical means. 

Police officers must follow strict and specific procedures for administering standardized field sobriety tests. Failing to follow the requirements for testing could make the results subject to challenge in court.

Even though the NHTSA only has three standardized DUI field sobriety tests, police officers often use several non-standard field sobriety tests during a DUI investigation. In addition to the finger-to-nose test, a police officer may use  the following tests to judge your impairment level during a DUI investigation:

Hand Pat Test

You extend your hand out in front of your palm up and then place your other hand on top of that hand palm down, as if you are about to start clapping. Then, counting “one, two, one, two, etc.,” you pat your hands together. Your bottom hand remains stationary. 

However, you turn the top hand from palm down to palm up between each movement. The result is that you “pat” your bottom hand with your top hand palm down on the “one” counts and palm up on the “two” counts.

Romberg Balance Test

During this test, you stand with your feet together and your head slightly tilted backward. Then, with your eyes closed, you must estimate when 30 seconds have passed. At that time, you tilt your head forward, open your eyes, and say stop.

Finger Count Test

The police officer instructs you to put one hand in front of you with your palm facing upward. You then touch your thumb to the tip of each finger, beginning with your index finger and ending with your little finger. As you touch each finger, you count from one to four. Then, the process is reversed and performed three times. 

As with standardized field sobriety tests, police officers observe your ability to follow instructions, coordination, balance, body tremors, and comments made during these non-standardized field sobriety tests. The purpose is to determine if you are impaired by alcohol or drugs.

However, the results of these non-standardized field sobriety tests are also highly subjective. The same problems exist with these tests as with the finger-to-nose test.

Using the Finger-to-Nose Test to Examine the Cerebellum and Measure Ataxia

The instructions provided for the finger-to-nose test are designed to help measure ataxia. Ataxia is the lack of muscle control or coordination of voluntary movements. It may be caused by alcohol use. 

The finger-to-nose test is supposed to detect a lack of voluntary coordination of voluntary muscle movements. A lack of coordination could indicate problems with the cerebellum, which could indicate intoxication. 

Because the finger-to-nose test is not a standardized test, the instructions police officers give to suspects can vary. However, general instructions include:

  • Stand with your feet together and your arms down at your side
  • Make a fist with each hand, keeping the index finger extended and turn your hand so your palm faces upward
  • Tilt your head back slightly
  • Close your eyes (closing your eyes before tilting your head back could impair normal equilibrium)
  • Extend your right (or left) arm straight out in front of your body and then touch your index finger to your nose before returning your arm back down to your side

As you perform the test, the police officer watches for “clues” or indicators of neurological dysfunctions that suggest you may have been driving under the influence of drugs or alcohol. 

Specific “clues” the police officer notes include:

  • Your inability to follow instructions, such as keeping your feet apart or extending the incorrect finger when making a fist.
  • Being unable to stand still. You sway from side to side or back to front, so the police officer finds that your inability to maintain balance is a sign of impairment. 
  • You exhibit the “shakes” because you involuntarily tremble when performing the test. Your muscle tone may appear more rigid or limp than is expected for a sober person.
  • You utter unusual sounds or make statements that the officer believes indicate you are intoxicated, such as signing while performing the test or repeatedly stating you have to “pee.”
  • You take too much time or you try too fast to touch your finger to your nose. Either action could indicate a problem with depth perceptions. 
  • The officer notes whether you use the correct sequence for touching your nose that the officer gave you.

As stated above, the results of the finger-to-nose test are subjective. For example, an officer might believe that asking to use the bathroom is an unusual statement, while another officer might assume that you just need to urinate. Likewise, belching could be interpreted as being intoxicated, but it could result from having just eaten a large meal.

Therefore, the reliability of the finger-to-nose test can be questionable.

Challenging the Results of the Finger-to-Nose Test 

Because the NHTSA has not approved the finger-to-nose test, police officers do not have a specific list of criteria to use when determining if a person “fails” the test. Furthermore, the procedure for administering the test can vary significantly from one jurisdiction to another and even more from one officer to another. Therefore, the validity of the test and the accuracy of the results are subject to scrutiny.

Additionally, there are numerous reasons why a person could fail the finger-to-nose test that have nothing to do with intoxication. Conditions or circumstances that could impact the results of the finger-to-nose test include, but are not limited to:

  • Ataxia caused by medications instead of being caused by alcohol intoxication. Certain medications may cause a lack of coordination of muscle movements, such as anti-seizure medications and medications for depression.
  • Brain damage and neurological defects could negatively impact the function of the cerebellum, which may impact coordination. 
  • Mental disabilities may prevent a person from understanding the instructions given by police officers when performing the finger-to-nose test.
  • Roadside conditions could impact the results of the test. For example, load noises from traffic, flashing lists, and other distractions could be the cause of the “clues” of intoxication the officer notes instead of alcohol use.
  • Incorrect sequences of instructions could impair the person’s equilibrium. Therefore, if a police officer tells the person to close their eyes and then tilt their head back, the test results could be invalid.

Without standardization, the results of a finger-to-nose test at a DUI stop can be inaccurate. Furthermore, without standard instructions to guide officers in judging the “clues” they observe during the test, it is impossible to know whether a police officer judged the person’s responses too harshly.

A DUI defense attorney can argue that the inherent defects in the finger-to-nose test make the results inconclusive, especially if there is no other evidence that the driver was intoxicated. 

Talk with a DUI defense lawyer if your DUI arrest was based partially on a finger-to-nose test. You may have a strong defense that could result in a dismissal of charges.

DUI Sobriety Checkpoints in California – Do Police Need Probable Cause?

No, California law enforcement officers do not need probable cause to stop a motorist at a DUI sobriety checkpoint. You could get arrested legally at a DUI sobriety checkpoint without the officer having probable cause to stop you.

You could, however, challenge the arrest if the checkpoint did not meet all the legal requirements our state law imposes on DUI sobriety checkpoints. A California DUI attorney can talk with you and examine whether a dismissal of the charges could be possible.

The Requirements for a DUI Sobriety Checkpoint to be Legal Under the California Constitution

In the 1987 case of Ingersoll v. Palmer, the California Supreme Court compared sobriety checkpoints to other administrative inspections, like airport screening searches. The Court held that law enforcement officers do not have to follow the 4th amendment at DUI roadblocks because these are administrative inspections, not searches and seizures.

The Court explained its decision to treat sobriety checkpoints as administrative inspections, not as searches and seizures, because “the primary purpose of the stop here was not to discover evidence of a crime or to make arrests of drunk drivers but to promote public safety by deterring intoxicated persons from driving on the public streets and highways.” 

As such, the California Supreme Court said that sobriety checkpoint stops do not require an individualized suspicion of wrongdoing. Instead, the Court said that the California constitution requires balancing the intrusiveness of the detention against the governmental interests.

Other Types of Regulatory Inspections and Stops

The Court in Ingersoll gave several examples of regulatory inspections in the stops that are legal according to the United States Supreme Court and California courts without the need for an individualized suspicion of wrongdoing. These include:

  • Border Patrol or immigration checkpoint inspections
  • Agricultural inspection checkpoints
  • Vehicle mechanical inspections
  • License and registration inspection checkpoints

The California Supreme Court in Ingersoll said that DUI sobriety checkpoints create a lesser intrusion on the individual’s 4th amendment interests than Border Patrol or immigration checkpoint inspections because, during the brief sobriety detention, neither the vehicle nor the occupant gets searched. The driver only needs to answer a question or two and possibly show the officer one’s driver’s license, registration, and proof of insurance.

The Justification for California DUI Sobriety Checkpoints

Law enforcement agencies across the United States have used a variety of approaches to try to address the drunk driving problem. Public awareness campaigns, increased patrols and arrests, and more severe penalties for DUI convictions have done little to tackle one of the most significant challenges, which is that the public knows that their risk of getting caught driving while intoxicated is quite low.

The California Highway Patrol (CHP) developed a pilot project of sobriety checkpoints in order to try to discourage people from driving after consuming alcoholic beverages. The CHP said they would rather deter drunk driving than have to make arrests and charge people with DUIs. The goal, according to law enforcement, is to decrease DUI arrests and alcohol-related accidents, not increase them.

Of course, when law enforcement officers break the rules and set up an illegal DUI sobriety checkpoint for the purpose of trapping unsuspecting drivers, there might be grounds for challenging an arrest.

California Supreme Court Created Functional Guidelines to Minimize the Intrusiveness of DUI Sobriety Checkpoint Stops

The Ingersoll court articulated eight requirements for legal DUI sobriety checkpoints in California. These guidelines are:

  1. The typical law enforcement officer in the field cannot decide on his or her own to set up a sobriety checkpoint. The risk of allowing that conduct is the potential for arbitrary and capricious enforcement of the law. Instead, supervisory or command-level law enforcement personnel are the only ones who can legally decide to use a checkpoint, select the location, and create the operational procedures. The upper-level law enforcement personnel must distribute detailed program regulations to the officers who will work at the checkpoint.
  2. Officers in the field will have strict limits on their discretion when working at DUI sobriety checkpoints. An officer will not be allowed to decide to stop any particular driver or car without a legitimate basis for that decision. The field officers must use a neutral formula, for example, stopping every single driver who pulls up to the checkpoint or, in the interest of keeping traffic flowing, only stopping every 5th or 12th driver or some other neutral formula.
  3. The sobriety checkpoint must not create an unsafe condition for motorists or officers. To minimize the risk of danger to drivers, passengers, and police, the law enforcement personnel must be clearly identifiable as officers. They must use clearly marked official vehicles. The checkpoint must have sufficient warning signs, signals, and lighting to create a safe environment. If traffic becomes backed up because of the randomized stops, the field officers can adjust the neutral formula or temporarily suspend making stops until traffic clears.
  4. The location of the checkpoint must be reasonable. Because the governmental interest is to deter people from driving while impaired by alcohol, the supervisory law enforcement personnel who select the locations should choose sites that will be most effective in achieving that interest. In other words, sobriety checkpoints should be set up on streets that have a high number of alcohol-related arrests or accidents. 
  5. A checkpoint must balance intrusiveness and effectiveness in terms of the time of day that the officers operate the checkpoint and how many hours the checkpoint will be operational. Safety is also an issue. A DUI sobriety checkpoint is more likely to be effective if it operates during the hours when people are more likely to drive while impaired by alcohol, for example, late at night and in the very early morning hours. Operating a checkpoint doing during those hours, however, could be more hazardous to motorists and officers.
  6. Motorists need to be able to tell at a glance that the DUI roadblock Is official and authorized and is not operated by rogues waylaying unsuspecting motorists. The general public is wary of criminals who impersonate police officers. The roadblock should incorporate flashing lights, warning signs, and adequate lighting. The fact that it is a sobriety checkpoint should be highly visible. Uniformed officers and marked police vehicles must be present. The government agency must provide advance warning of a DUI checkpoint to minimize intrusiveness to motorists and to reassure them that the roadblock is legitimate.
  7. Supervisory law enforcement personnel must promulgate detailed guidelines on the length and nature of the detention of the random drivers who get stopped in DUI sobriety checkpoints. The stops must be as brief as possible for the officer to ask the driver one or two questions and look for signs of intoxication. If the driver does not show symptoms of being impaired by alcohol, the driver should not be delayed any further from driving on down the road. When an officer observes signs of alcohol use, the officer can direct the driver to a separate area of the checkpoint for field sobriety tests. In the separate area, those officers would have to have probable cause to conduct further investigation. The incident would no longer be an administrative inspection, but rather, the constitutional protections around traffic stops and arrests would apply to the situation.
  8. As mentioned earlier, the government agency must provide advance publicity. A DUI sobriety checkpoint without sufficient advanced publicity could be considered arbitrary and capricious and violate the constitutional rights of motorists. The general public should get informed that law enforcement will be conducting sobriety checkpoints at specific locations, dates, and times. This publicity would serve the governmental interest of deterring drunk drivers from using those streets. The ultimate goal of the warning is that people would do their driving at home, take a taxicab if they have had too much to drink, or choose not to drink to the point of impairment from alcohol before driving.

When police departments set up DUI sobriety checkpoints that violate one or more of these eight guidelines, a person arrested at such a stop might have grounds to ask the judge to dismiss the criminal charges. The enforcement of traffic law must comply with state and federal constitutional protections. Police officers must minimize intrusiveness on the lives of the general public.

Signs of Intoxication

Officers working at sobriety checkpoints in California are allowed to ask one or two brief questions of the people they briefly detain. The purpose of asking the questions is to give the police officer the opportunity to look for symptoms of alcohol impairment of the driver, including:

  • Fumbling when trying to locate one’s driver’s license to show the officer
  • Bloodshot or glassy eyes 
  • Slurred speech when talking to the officer
  • Smelling alcohol on the breath of the driver or in the vehicle

The police officer is not limited to these examples of intoxication symptoms. The officer can direct the driver to another area of the checkpoint for additional investigation as long as objective facts support probable cause or reasonable suspicion that the driver is impaired by alcohol.

What Happens if a Driver Does Not Cooperate with the Officer at a DUI Checkpoint

The consequences of refusing to comply with the instructions from a law enforcement officer at a DUI sobriety checkpoint depend on the point at which the driver does not cooperate. California law requires everyone who operates a motor vehicle on public streets to cooperate with DUI sobriety checkpoints. 

You will likely be charged with violating the traffic laws if you do not follow the directives of uniformed law enforcement at a legal California sobriety checkpoint. 

Because the checkpoint is an administrative inspection, not a regular traffic stop, taking a field sobriety test, breathalyzer, or other tests before getting arrested is optional. If you refuse, however, the officer will likely arrest you for DUI, at which point refusing a breathalyzer or similar test will get your license suspended automatically for one year, in addition to other consequences.

If you or someone you know is facing a DUI, a California DUI attorney can help to protect your legal rights and aggressively pursue the best possible outcome in your situation.

Rules for Obtaining a Blood Sample After a DUI Arrest

There is much confusion over the rules for obtaining a blood sample after a DUI arrest. Many people are unclear of the laws regarding DUI cases and what’s permitted in court. Do you have to submit to a blood test? What can affect a blood alcohol test? This blog will answer these questions and more. 

Here, you will learn what your rights are while gaining a comprehensive understanding of the DUI blood test. If you have already submitted to a blood test or you’re facing a DUI case, this article will offer guidance and direction as to how to proceed.

What is a DUI Blood Test?

The term “DUI” is an acronym for Driving Under the Influence. Moreover, DUI means operating a motor vehicle while intoxicated with drugs or alcohol. Every state has its own DUI law that dictates it is illegal to drive while intoxicated, whether under the influence of alcohol, marijuana, prescription medication, or illicit drugs. 

What’s more, some states have laws in place that differentiate between the various possible DUIs, such as one involving alcohol and one involving an over-the-counter medication like cough syrup. And it’s because there are so many possible scenarios involving DUIs that blood tests exist.

Blood tests help determine the blood alcohol content (BAC) in persons charged with DUI. If you are pulled over, and the police officer determines that you are intoxicated, blood testing can be ordered. 

But unlike breathalyzers, blood tests are almost never performed at the scene of the arrest. Unless there is a unique situation where a qualified medical practitioner is present at the scene and has the necessary equipment to legally do so, all blood tests take place in a medical facility.

Moreover, blood alcohol testing in hospitals ensures that proper laws regarding chemical testing are followed. Some states have strict regulations in place that dictate who can take a blood sample and test alcohol levels, as well as the manner in which the samples are analyzed and transported.

It’s rare that police officers are trained and equipped to administer blood tests. And even you are pulled over for DUI by an officer that can perform blood draws, your state’s laws may prohibit them from doing so at the scene.

If you discover that someone took a blood sample from you who wasn’t qualified to do so, you can legally challenge the results of the blood test.

What Can Affect a Blood Alcohol Test?

Blood alcohol tests are used to determine the blood-alcohol concentration (BAC) of a driver suspected of driving while intoxicated. BAC is defined as the amount, by weight, of ethanol in 100 milliliters of blood or 210 liters of breath. 

There are a number of factors that can affect the validity of this test. Some things that may cause an inaccurate reading include time from alcohol consumption, having diabetes, taking certain medications, or eating food right before the test. 


Your body absorbs alcohol the moment you consume it, and it does so quite efficiently. However, it can take as much as 60 minutes for your blood alcohol concentration to reach its peak. Therefore, it is very likely that a blood alcohol test conducted 30 minutes before or 30 minutes after the peak 60-minute mark would yield very different results.


This is a very significant factor that can radically change blood alcohol levels. For instance, some medicines can cause a person’s body to respond in a way that limits the effects of alcohol, while other medications can actually make the effects worse.


The more food you have in your body, the longer it takes you to absorb alcohol into your blood. Therefore, if you and a friend have been drinking the same amount of alcohol, but you have an empty stomach, it’s likely that testing you both would should you to have a higher blood alcohol level.

What is the Legal Limit for Blood Alcohol Content?

In every state, the legal limit for BAC is 0.08%. However, the limits vary when it comes to increased penalties. For example, the California BAC limit is 0.08%, with penalties increased for anyone caught driving with a blood alcohol content of 0.15% or higher.

If you are facing DUI charges, it is important to secure the legal counsel of a qualified DUI attorney. Your lawyer will ensure your rights are not violated.

For your blood test to count as evidence in court, prosecutors must follow what’s called the “chain of custody.” This means that they must establish the following to the court in order for the blood test to be accepted as evidence:

  • Who performed the blood draw
  • Whether they were qualified
  • Where it was taken
  • How it was taken
  • Who analyzed it
  • Their qualifications
  • Protocols in place to ensure your sample was constantly accounted for
  • Protocols in place to ensure testing equipment was constantly accounted for
  • The use of a common testing method
  • Proper storage and transport of sample

In addition, there is special documentation in place that must be signed and dated every time a blood sample changes hands. In DUI defenses, attorneys carefully research and review the above requirements and make sure the proper paperwork was used throughout your testing.

If anything was ignored, overlooked, or protocol wasn’t followed correctly, your attorney will fight to have your sample disqualified as evidence.

Penalties for Refusal of a Chemical Test

Each state has its own implied consent law, which can result in penalties for refusing to take a chemical  test- whether a breath or  blood test- when authorities have a basis for believing you are operating a motor vehicle while under the influence. What type of penalties you might face depends on the state in which you are pulled over. However, while you can face additional penalties for refusing to take a blood test and the refusal can be used as evidence of guilt at trial, you cannot face a separate criminal charge for refusal of a blood test.

Blood Test Administration: How It Works

If you do anything to purposefully delay the test, the police may deem you a refusal. With that said, you can request that a different type of test be administered to you, such as a breath test if it is available.

Just be aware that if alternative tests aren’t available, you must agree to the blood test. Upon administration, a qualified person will use a syringe to draw blood from a vein. That sample is stored in a vial that is then sent off for analysis.

If you are concerned about the way your blood test was handled or you want to ensure that you are fairly represented, contact a trusted DUI attorney today.

Avoiding Jail Time in a California DUI Case


Whether a driver faces DUI charges in California or any other state, there is one potential consequence that is likely to be of concern to the person: incarceration. There is good reason for such concern: even a few days spent in jail can lead to a reduction in income or job loss. Not only this, but any time that a parent spends away from their child or that a spouse spends away from their partner can cause emotional hardship. All of this is on top of the harm to one’s reputation that might result from serving time for a DUI conviction.

First-Time DUIs Do Not Usually Lead to  Jail Time

A person is unlikely to face jail time for their first DUI conviction. While the maximum sentence   for a first-time DUI includes six months in jail, this outcome is not likely in many cases. Most first-time DUI offers include a period of  three years of informal probation, approximately $2,000 in fines and fees, a 3-month DUI program, the MADD VIP program, and restitution if there was a collision.

Drivers convicted of their first DUI and whose cases involving aggravating factors are more likely to face jail time. Such factors can include:

· Causing injuries

· Excessive speeding

· Reckless driving

· Driving on a suspended license

· Having a blood- or breath-alcohol concentration that is significantly higher than the legal limit.

Thus, drivers convicted of their first DUI may need not worry about having to serve jail time. Instead, they will likely placed on a period of informal probation. If there are aggravating factors involved, however, then the driver faces a greater risk of incarceration

Subsequent DUIs

Once a person is convicted of a subsequent DUI in California within a 10 year period, courts are required to sentence the person to some period of incarceration. Under these circumstances, it becomes even more important to challenge the prosecution’s case. There are several areas where the prosecutor’s case may be vulnerable:

· Lack of evidence of essential elements: The prosecution must be able to prove that the defendant was driving a vehicle. If there are no witnesses who saw the person driving and there is little circumstantial evidence suggesting the person drove a vehicle, the prosecutor may not be able to win their case. 

· Suppressed breath or blood test results: If law enforcement officers did not follow the proper steps in collecting, preserving, and testing a person’s breath or blood sample, then a court may rule that any results obtained from testing of those samples are to be suppressed (kept out of court). Test results may also be suppressed if they were obtained in violation of the person’s constitutional rights. Without being able to present test results showing the driver’s blood or breath alcohol concentration, the prosecutor may lack the evidence they need to show the person was impaired at the time they were driving a vehicle.

· Inaccurate or inconclusive breath or blood test results: There are a number of reasons why a breath testing machine may not give an accurate result, especially if the driver has an underlying medical condition or follows a ketogenic diet. Similarly, a blood sample may not be suitable for testing if the individual who collected the sample did not follow the proper protocol in collecting, storing, or analyzing the sample. 

· No evidence of prior convictions: If the prosecutor is alleging that a person charged with DUI has one or more prior convictions, then the prosecution must be prepared to present evidence of those prior convictions. An erroneous entry on a person’s driving history or criminal record that cannot be substantiated may mean the difference between a second DUI conviction and mandatory jail time and a first DUI conviction and informal probation.

Drivers Charged With A DUI Should Seek Legal Assistance

While a first-time DUI will most likely not lead to incarceration, there are no guarantees. Even a person’s first DUI conviction, when accompanied by a high BAC, a collision involving injury, and/or other aggravating factors, may result in a jail sentence. Motorists with subsequent convictions within a 10 year period will face incarceration. Therefore, any individual who is facing a California DUI charge and who is concerned about incarceration should speak with an experienced California DUI defense lawyer about their case as soon as possible.


Low-carb diets -such as the Atkins diet or the Ketogenic diet- have been around for decades. Nonetheless, this type of diet can cause problems for California drivers. It may cause a breath test provided by a California driver who was pulled over or arrested on suspicion of a DUI to falsely show the presence of alcohol – even if the driver had not consumed any alcohol that day.

Here’s how: A low-carb diet deprives the body of glucose, an important source of fuel for the body. In the absence of this source of fuel, the body turns to its fat for fuel. The process of turning fat into fuel produces ketones. When the body produces ketones and uses them for fuel, the body is in a state of ketosis. When the body is in a state of ketosis, ketones can be detected in that person’s breath. (This explains the bad breath that some report while on a low-carb diet). These ketones have a chemical composition similar to isopropyl alcohol. Many breathalyzer testing devices cannot distinguish between isopropyl alcohol molecules and ethyl alcohol molecules.  As such, a breath testing machine used in a DUI investigation may falsely detect the presence of alcohol simply because the suspect is on a low-carb diet.

It is doubtful that the amount of ketones in anyone’s breath could be sufficient to result in a breath test result showing a blood alcohol concentration at or greater than the .08% legal limit without the person having had consumed some alcohol. However, a person who would have otherwise been below the .08% legal limit may end up with a breath test result at or greater than the legal limit if that person is in ketosis. For example, someone who is in ketosis and has a true blood alcohol concentration of .06% could potentially register at 0.08% or more.

California Vehicle Code 23612(a)(2)(A) allows drivers arrested for suspicion of a DUI to choose between submitting to a breath test or a blood test. Unless the chosen test is not available, the officer must perform the test selected by the driver. Drivers on a low-carb diet may want to avoid submitting to the breath test to avoid being stuck with a false positive result.

Any driver arrested for a DUI should immediately hire an attorney. If you are on a low-carb diet, it is crucial that you tell your attorney.