Category Archives: Field Evidence

Contesting Breath Alcohol Tests with Partition Ratios

DUI breath tests are standard tools used to prove someone was driving under the influence of alcohol in California. However, breathalyzer tests are not always accurate. Furthermore, the breathalyzer does not measure the amount of alcohol in your bloodstream, so there is the opportunity to contest the accuracy with partition ratios.

How Does a Breath Test Work for a California DUI?

Police officers use two types of breath tests to determine if a driver was intoxicated while driving. First, the roadside preliminary alcohol screening (PAS) test is a roadside breathalyzer. It is given during a DUI stop and investigation.

You can refuse the PAS test without penalty unless you are under 21 years of age or on DUI probation. You can also refuse to take a cheek swab or perform the field sobriety tests too. However, you cannot refuse the second breath test without penalty.

The second breath test is a post-arrest evidentiary breath test. You cannot refuse a chemical BAC test after your arrest without penalty. These are evidentiary tests, meaning the state can use the results in court. 

Most drivers choose between the post-arrest breath test and the blood test. However, the person may be required to take a blood test if the officers believe they have drugs in their system (DUID), they cannot blow hard enough for the breath test, or the driver is unconscious or in a medical facility where a breath test is not available. 

How Does a Breathalyzer Test Work?

Understanding how to challenge the results of a breath alcohol test using partition ratios in California helps to understand how breath tests work. DUI breath tests do not measure the blood alcohol level in your bloodstream. Instead, they measure the amount of alcohol in the deep lung air.

Deep lung air comes from the alveoli located deep within the lungs. Tiny blood vessels surround the alveoli. The blood vessels allow oxygen to pass from the lungs into the bloodstream and allow carbon dioxide and other substances, like alcohol, to pass from the blood to the alveoli. 

The alcohol concentration is highest in the alveoli. Therefore, an evidentiary breath test uses the air from this area to test for alcohol in your system. However, you must blow very hard to get the air from the alveoli into the machine. Some individuals may not be able to blow hard enough and might need a blood test.

How Can the Partition Ratio Lead to Inaccurate BAC Levels?

Since the breath test measures the amount of alcohol in your lungs, the results must be converted to a rough equivalent of a BAC. The mathematical conversion is known as the partition ratio. 

California laws set the partition ratio for breath-testing at 2,100 to 1. In other words, the amount of alcohol in 2,100 milliliters of breath is equal to the amount of alcohol in 1 milliliter of blood.

However, everyone’s body is unique. Your partition ratio may differ from the fixed partition rate because everyone’s lungs absorb the alcohol at a different rate. 

How Does the Partition Ratio Impact a DUI Case?

Under California Vehicle Code §23152, it is unlawful for you to operate a motor vehicle if:

  • Your BAC is .08% or higher (per se charge) OR
  • You are under the influence of any alcoholic beverage (generic dui charge)

A per se DUI is where the person’s BAC is .08% or higher. The law presumes that you were too drunk to drive if you have a BAC over the legal limit. Therefore, if your breath test shows a BAC of .08% or higher, you are presumed to be too impaired to operate a motor vehicle.

However, if your BAC is below the legal limit, you are charged with a generic DUI. The prosecution must show that the alcohol in your system actually impaired your ability to operate the motor vehicle safely. In cases with BAC close to the legal limit, the prosecutor might get a conviction if there is other evidence the driver was intoxicated. 

On the other hand, if the person’s partition rate is not 2,100:1, the person’s BAC level might be much lower than the level alleged by the prosecution. If so, the person may not have been impaired by alcohol when they were pulled over for a DUI stop.

Challenging the Results of a BAC Level Using Partition Ratios

In July 2009, the California Supreme Court decided an important case that changed how some people defend themselves against the generic DUI charge. The decision in People v. McNeal allows a defendant to contest the accuracy of a breath test by submitting evidence their partition ratios are not equal to the ratio set by law. Defendants may also challenge the results by offering evidence proving the variance of partition ratios among the general public. 

In a borderline BAC case, offering evidence that the defendant’s individual partition ratio is different from the state’s ratio could create reasonable doubt for the jury. Especially when there is no substantial evidence other than the breath test that proves the defendant was intoxicated while driving.

If your DUI case relies on the results of a breath test, talk with a California DUI defense lawyer before accepting a plea deal. You may have grounds for challenging the results to prove you were not drunk while driving. 

Other Ways to Challenge an Evidentiary Breath Test in a DUI Case

In addition to challenging the accuracy of the breath test results based on partition ratios, there are other ways to attack a breath test. For example, the California Code of Regulations Title 17 sets the rules for DUI chemical testing procedures. As a result, the samples could be invalid when labs and law enforcement officers do not follow these rules.

There are many rules under Title 17 for performing a breathalyzer test after a DUI arrest. Some important rules include:

  • The device must be calibrated every 150 uses or ten days, whichever comes first
  • The person giving the breathalyzer test must be trained to use the specific device
  • The DUI breathalyzer device must be in good working order
  • Air from deep within the lungs must be collected to perform the test
  • The driver must be watched continuously for 15 minutes before the DUI breath test to ensure they did not eat, drink, or put anything in their mouth, smoke, vomit, burp, or regurgitate
  • The lab must keep detailed records of the personnel, equipment calibration, and test results
  • Two breath samples do not differ by more than 0.02 grams per 100 milliliters of blood must be obtained

Violation of any of the above Title 17 rules could result in inaccurate BAC levels that are not as high as they appear. A DUI defense lawyer reviews the testing procedures and records to determine if the lab or law enforcement agency made errors that could support a challenge to the breath test results.

Medical Conditions and Other Factors Could Result in Incorrect BAC Breath Test Results

In addition to problems with the machine and errors made by law enforcement agents or lab workers, a person’s medical conditions could affect the accuracy of a breath test. Specific health conditions can result in falsely high BAC levels. 

Examples of medical conditions or other factors that could affect the BAC results from a breathalyzer include: 

  • Diabetes
  • Gastrointestinal reflux disease (GERD)
  • Low carb/high protein diets
  • Residual mouth alcohol
  • Inhaling acetone and other volatile chemicals
  • Rising blood alcohol levels
  • Medication, food, or mouthwash caused a false high
  • Dentures caused the alcohol to pool in the mouth

There are many ways to challenge an evidentiary breath test. It is worthwhile, especially in cases where the BAC level may be just below the legal limit. Challenging the accuracy of the test can help jurors accept your argument that you might have had some alcohol, but you were not impaired to drive.

What Should I Do After a DUI Arrest in California?

Do not panic. You have not been convicted of driving under the influence. However, the matter is extremely serious. The punishments for a DUI conviction in California can be harsh.

Therefore, do not talk to the police. The police officers and the prosecutor already believe you are guilty. Any information you give them only makes their case against you stronger.

Instead, remain quiet until you speak with a California DUI defense attorney. Your attorney discusses the facts of your case, your legal rights, potential defenses, and the best options you have for fighting the DUI charges. 

You might want to fight the drunk driving charges based on your attorney’s advice. You might have a solid challenge to the evidentiary breath test results based on partition ratios or errors regarding the test. 

If not, your attorney works to negotiate the best plea bargain possible. A prosecutor may be willing to work out a better deal with an attorney than directly with you. 

The prosecutor knows if a deal is not struck, the case goes to trial. That might not be in the prosecutor’s best interest. Furthermore, the prosecutor has hundreds of cases to handle. They want a win, not a hard fight for a potential acquittal.

Ensure you know your legal rights after a DUI arrest to reduce the chance of jail time and other penalties.

Are California Drivers Required to Take a Field Sobriety Test?

Law enforcement officers rely heavily on field sobriety tests (FSTs) in California to determine if a driver is impaired by alcohol or drugs during a traffic stop. The FSTs may be the only “evidence” an officer collects during a DUI investigation to justify an arrest for driving under the influence. The theory is that poor performance on field sobriety tests indicates alcohol or drug impairment. 

However, these “standardized” field sobriety tests are not perfect. Even if the conditions are ideal and the police officer administers the FSTs precisely as directed by the NHTSA guidelines, the results of field sobriety tests can be inaccurate. According to the Instructor Guide provided by the National Highway Traffic Safety Administration, the accuracy levels for the FSTs are:

  • Walk and Turn Test – 79% accurate
  • One Leg Stand Test – 83% accurate
  • Horizontal Gaze Nystagmus Test – 88% accurate

California drivers need to understand their rights regarding field sobriety tests. For example, a California driver does not have to take the field sobriety tests when stopped for suspicion of drunk driving.

California Drivers Can Refuse to Take Field Sobriety Tests

If you are pulled over for drunk driving, the police officer will ask you to take the field sobriety tests. He is looking for signs of impairment based on your performance on the FSTs. California does not impose any penalty for refusing to take field sobriety tests during a traffic stop.

As experienced DUI defense lawyers, we generally recommend that California drivers respectfully decline to take field sobriety tests for several reasons. Primarily, a sober person can fail a field sobriety test for reasons that have nothing to do with alcohol or drugs in their system. 

Unlike chemical tests (i.e., urine, blood, or breath test) that determine your blood alcohol content (BAC), the field sobriety test the officer gives you is a subjective review of “signs” that could indicate you are a drunk driver. The officer may have already made up his mind about arresting you for drunk driving. Taking the FSTs gives the police officer additional “evidence” to present to the court that justifies the DUI charges.

Failing field sobriety tests could result in one or more charges under the California Vehicle Code, including driving under the influence and DUID (driving under the influence of drugs).

To help you understand how California field sobriety tests work and how the results can be incorrect, we discuss the standardized FSTs and some non-standard field sobriety tests used by California police officers during a DUI stop.

DUI Field Sobriety Tests Used in California

As discussed above, the NHTSA has approved three field sobriety tests to be used by police officers during a roadside DUI investigation. The NHTSA considers these tests to be good indicators of a person’s impairment. 

The NHTSA bases its “validation” of these tests in part on a study by the Sand Diego Police Department. The study reported a strong connection between poor performance on these tests and alcohol or drug impairment. The tests are collectively referred to as the “standardized FSTs.” 

The Walk and Turn Test (WAT Test)

This divided attention test requires a person to simultaneously concentrate on a physical and mental task. For the test to be accurate, the police officer must give the person exact instructions for completing the test. The person must remember the instructions and complete them in order correctly.

Generally, the police officer tells the person to take nine heel-to-toe steps in a straight line (either a line on the road or an imaginary line). After completing nine heel-to-toe steps, turn around and take nine heel-to-toe steps back to the beginning point.

There are eight signs that the police officer may notate that could indicate the person is intoxicated or under the influence of drugs:

  • Starts walking too soon
  • Cannot maintain balance during the instructions
  • Fails to walk in a heel to toe fashion
  • Uses the arms to balance 
  • Takes the wrong number of steps
  • Stops while walking
  • Steps off the line
  • Fails to make the turn correctly

This FST has a 79% accuracy rating for indicating a BAC of .08 or greater because of poor performance. There could be many reasons why a person is unable to maintain balance while walking heel to toe.

The Horizontal Gaze Nystagmus Test (HGN Test)

Nystagmus is the involuntary movement or “jerking” of the eyes from side to side, up and down, or in a circle. Horizontal nystagmus describes the uncontrollable and rapid movement of the eyes from side to side. 

The HGN test given during a roadside field sobriety test involves the police officer noting the angel of the eye when it begins to “jerk” (exhibit nystagmus) as it moves side to side. The officer performs the test by moving a stimulus, such as a pen, from left to right and instructing the person to follow the object with their eyes.

Nystagmus at or before the 45-degree angle of the eye movement is associated with a high level of alcohol in the person’s system. However, the accuracy level of the HGN test is roughly 88%, according to the NHTSA. Therefore, the results of this field sobriety tests could be incorrect in at least 12% of the cases.

The One Leg Stand Test (OST Test)

This field sobriety test is another divided attention test used during a DUI traffic stop. While this test has a better accuracy rating according to the NHTSA, it still leaves a lot of room for errors.

During the OLT test, the police officer instructs the person to lift their foot about six inches off the ground. While holding that position, count from 1001 to 1030 and then look down at their foot.

Signs of impairment that the officer looks for during the test include swaying, hopping, using the arms to balance, and putting the foot down before completing the test.

Non-Standard DUI Field Sobriety Tests Used by Police Offices

In addition to the “standardized” field sobriety tests, police officers use various non-standard field sobriety tests during a DUI stop. The NHTSA has not approved or validated these tests because there is little to no evidence that poor performance on these tests indicates DUI impairment. Furthermore, the way the tests are administered can vary significantly from one law enforcement officer to another, increasing the chance that the test results are inaccurate. 

Several “signs” the officer looks for when performing these non-standard FSTs include:

  • Ability to follow instructions, including counting correctly, starting and stopping correctly, and remembering instructions 
  • Ability to balance and stand still
  • Muscle tone and body/eye tremors
  • Depth perception 
  • Uttering unusual phrases or sounds
  • Lack of muscle control
  • Ability to perform mental and physical tasks simultaneously 

Some of the non-standard field sobriety tests used by California police officers include:

Finger Count Test

The police officer instructs the person to extend their hand with the palm facing upward in front of their body. Then, touch the top of the thumb to each finger, beginning with the index finger and working their way over to the little finger. While touching each finger, the person should count from one to four aloud. Then, the process is reversed for a total of three sets. 

Finger to Nose Test

This non-standard FST is one of the most common field sobriety tests officers perform. First, a police officer instructs the person to stand with their feet together and their arms at their sides. Then, after making a fist with each hand and keeping the index finger extended, the person must tilt their head back and close their eyes. 

The officer then instructs the person to extend either the left or right arm in front of their body and use their index finger to touch their nose. If the person cannot perform the test correctly, it is thought to be a sign of intoxication because the person lacks muscle control and coordination.

Romberg Balance Test

A police officer instructs the person to stand with their feet together, and their head tilted slightly backward. Then, with their eyes closed, the person must estimate when 30 seconds have passed. Finally, when they believe 30 seconds have passed, they will tilt their head forward, open their eyes, and say stop.

Hand Pat Test

The officer instructs the person to extend either the left or right hand in front of their body with the palm facing upward. Then, place their other hand on the top of that hand with the palm facing down. 

Keeping the bottom hand in the same location, the person must use the top hand to “pat” the bottom hand while counting “one, two, one, two, etc.” In addition, the person must rotate their top hand on each of the counts so that they pat their bottom hand palm down on the “one” counts and palm up on the “two” counts.

What Can Affect the Accuracy of a DUI Field Sobriety Test?

Many things can affect the accuracy of DUI field sobriety tests. For example, there are several medical reasons why a person would exhibit signs of nystagmus, including multiple sclerosis, head injuries, certain medications, and cataracts. 

Numerous physical and mental conditions may affect the accuracy of a test. Age, weight, inner ear problems, mental disabilities, anxiety, physical pain, and illness are just a few examples of why a person could “fail” a field sobriety test when they are not impaired by alcohol or drugs. In addition, being tired, having muscle fatigue from work or exercise, and stress can negatively impact a person’s ability to perform field sobriety tests correctly.

Weather and field conditions can have a significant impact on FST results. For example, if the test is given on an uneven surface, it increases the chance the person will lose their balance. In addition, bright lights from oncoming traffic and noise can affect test results.

The police officer’s conduct can result in inaccurate test results. For example, if the police officer does not provide clear instructions, the person may “fail” the test. Likewise, if the officer moves around, it can distract the person and result in inaccurate test results.

Even something as simple as wearing high heels, tight clothing, or baggy pants could adversely affect a person’s performance on field sobriety tests.

Fighting the Results of DUI Field Sobriety Tests in California

If you are arrested for DUI in California, you should discuss your legal options with a DUI defense attorney before pleading guilty to driving under the influence. There may be one or more grounds for challenging field sobriety tests.

The 1650 Waiver to Attend DUI School Out-of-State

If you live in another state and get a DUI in California, you might find it inconvenient to have to attend an in-person California DUI school as a part of your sentence. Ordinarily, the California Department of Motor Vehicles (DMV) requires people convicted of DUIs to enroll in and complete DUI driving school here in California. 

A non-resident can request a waiver of the California in-person DUI school requirement by filing a 1650 waiver request. If you do not attend and complete an in-person DUI program in California and do not request and receive a waiver, your home state can deny you a driver’s license. Your only option then is to make repeated trips back to California to complete the DUI school.

How to Request a 1650 Waiver

You will have to wait until you are eligible to request that the California DMV terminate your DUI suspension or revocation. If the California DMV grants your request, you would not have to attend driving school in this state, and you will be able to apply for a license in your state of residence.

You must meet all of these conditions to be eligible for a termination of action as a non-resident:

  • Any suspension or revocation of your driving privilege is no longer in effect.
  • If you had any Administrative Per Se restrictions on your driver’s license, all such restrictions are no longer in effect.
  • You are no longer ordered by the court or the California DMV to have an ignition interlock device (IID) or any other court-ordered or DMV-ordered restrictions.
  • You have paid all applicable administrative service fees. 

You can check your driver’s record to verify these factors. You may request this information by telephone, online, or by regular US mail. After verifying that you have met all of the conditions, you will need to file an application for termination of action (DL4006) with the DMV, along with acceptable proof of out-of-state residency, payment of fees, and proof of financial responsibility, if required.

Application for Termination of Action (DL 4006)

The Application for Termination of Action must get sent to the Mandatory Actions Unit of the California Department of Motor Vehicles (DMV), with all the required documents and attachments. Before the termination of action under California Vehicle Code (CVC) section 13353.5 can happen, the Mandatory Actions Unit must verify that the applicant has met all of the conditions and requirements.

The applicant must swear under penalty of perjury that the individual is not a resident of California. Also, the applicant must voluntarily authorize the California DMV to cancel the individual’s California driving privileges if the DMV terminates the suspension or revocation as requested. It usually takes the California DMV a month or two to process the waiver packet.

Documents the DMV Will Accept as Proof of Out-of-State Residency

The DMV provides a list of 18 different kinds of documents they will accept to prove that you do not live in the state of California. You must submit at least one of these papers with your DL 4006 form. 

A few examples of the acceptable out-of-state residency documents for the 1650 waiver form (DL 4006 form) include:

  • A home utility or cell phone bill
  • Official voter registration documents
  • A mortgage bill
  • A rental or lease agreement signed by both the owner/landlord and the tenant/resident
  • An employment document
  • A property tax bill or statement
  • A change of address confirmation by the US Postal Service 

Whichever document or documents you choose to submit to show out-of-state residency must show your current out-of-state address that is the same as you provide on your DL 4006 form. 

What is Proof of Financial Responsibility?

Proof of financial responsibility in the context of driving means that a driver has automobile insurance that will pay the losses of people who get injured or property that gets damaged as a result of the driver. California tries to protect the general public from people exercising the privilege to drive without being financially responsible to people they might harm.

The DMV might require you to provide a California Insurance Proof Certificate (SR 22) from an insurance company authorized to do business in California. If your insurance is from a company not authorized to do business in California, the DMV will only accept that insurance document if you send in a Declaration Regarding Certificate of Insurance for Non-Resident Driver. That declaration is on the DL 300 form, California Proof Requirements for Non-Residents.

Who Needs a 1650 Waiver?

If you were a non-California resident and you got convicted of a “wet” driving offense, like:

  • Driving under the influence, Vehicle Code 23152(a),
  • Driving with a BAC of 0.08% or higher, Vehicle Code 23152(b)
  • Underage DUI with a BAC of 0.05% or higher, Vehicle Code 23140
  • “Wet reckless,” Vehicle Code 23103.5

You will have to enroll in and complete an in-person California DUI driving school unless you get a 1650 waiver of that requirement. A 1650 waiver comes with significant consequences. For starters, once you use a 1650 waiver, you can never get a second waiver in your entire lifetime. 

Also, you will not be allowed to drive in the state of California for three years, even if you become a California resident. If you do move to California, you will have to complete the DUI school before the DMV will issue you a California driver’s license.

Consequences in Your Home State

Getting an out-of-state DUI conviction does not let you fly under the radar in your home state. The California court will notify a non-resident’s home state of the conviction. Also, the DMV in California will suspend your California non-resident driving privileges.

You can face negative repercussions in both states, California and your home state, after getting convicted of a DUI here. Your state will treat the California conviction as if it happened in your home state. 

Your home state is allowed to impose its own penalties on you, even if they are more severe than the penalties the California court assessed. Typically, your home state will not allow you to drive legally using that state’s driver’s license until you satisfy all of the penalties of the California conviction, which include the DUI program requirements of the DMV. One of the program requirements is the California DUI school.

Can I Attend a California DUI School Online?

Generally, no. A person convicted of a DUI in California must attend a licensed DUI program unless the individual obtains a 1650 non-resident waiver. The Department of Health Care Services (DHCS) evaluates, licenses, and monitors the compliance of all California DUI programs. The Behavioral Health Licensing and Certification Division, Driving-Under-The-Influence (DUI) Section is the specific aspect of the DHCS that performs these tasks.

You cannot simply enroll in any DUI school or program. The DUI school must be California-licensed to satisfy the penalties under your conviction. DUI school hopes to give participants an opportunity to address their problems with using alcohol and drugs, and to reduce the number of second and subsequent DUI offenses by individuals. 

California DUI Programs

There are multiple levels of DHCS licensed DUI programs. For example:

  • If you get convicted of reckless driving and you had a measurable amount of alcohol in your bloodstream, you must complete the “wet reckless program,” which is a 12-hour DUI education program.
  • For a first-offense DUI conviction, the DMV requires the completion of a three-month 30-hour alcohol and drug education and counseling program. If the first offense was for a blood alcohol content of 0.20% or higher, the individual must complete a nine-month 60-hour alcohol and drug education and counseling program.
  • If a person gets a second or subsequent DUI conviction, there is a mandatory 18-month multiple offender program. The program includes 52 hours of group counseling, 12 hours of alcohol and drug education, six hours of community reentry monitoring, and biweekly individual interviews during the 12 months of the program.
  • For a third or subsequent DUI conviction, a county may choose to impose 30-month DUI programs, with 78 hours of group counseling, 12 hours of alcohol and drug education, 120 to 300 hours of community service, and close and regular individual interviews.

The high level of involvement and time required by California DUI programs make it difficult for someone who lives in another state to participate in and complete the program requirements.

COVID-19 FAQs for DUI School

During the COVID-19 pandemic, the state of California enacted measures to reduce exposure to the virus, including suspending or limiting DUI program services. Anyone participating in program services or wanting to enroll in the program could find limitations on the program due to COVID-19 restrictions. The DHCS supported telehealth services for DUI programs to minimize the spread of COVID-19.

Are There Additional Penalties for a DUI Conviction in California?

Yes, and you do not get to avoid these consequences just because you are not a California resident. Also, keep in mind that your home state can impose additional penalties. In California, a first-time DUI conviction could include these penalties:

  • DUI school
  • A six-month driver’s license suspension period
  • Up to six months in county jail
  • Installation of an ignition interlock device (IID) for six months
  • Fines and penalties adding up to as much as $1500 or $2000
  • DUI probation of 3 to 5 years
  • Work release

Getting a DUI conviction can impact your life in many other ways. You will want to work with a California DUI attorney to protect your rights if you get arrested for drunk driving.

What is the “Walk and Turn” Test for DUIs in California?

When a police officer pulls you over for suspected driving under the influence (DUI), it can be a nerve-wracking experience, even if you are completely sober. After collecting your license, insurance, and registration they will often ask you to exit the vehicle and will begin conducting one of several DUI field sobriety tests. No matter where you get pulled over, from San Diego to Los Angeles or anywhere else in California, you can expect to have to perform a standardized field sobriety test.

There are several types of field sobriety tests that can be administered during a traffic stop, and one of the most common is known as the walk and turn test. It is also called the 9-step test, and the DUI walk the line test. This is due to the number of steps that the law enforcement official administering the test will have the driver take before turning. 

We’re going to take a more in-depth look at this test, including how it is conducted, what the rules are, what the officer will be looking for, and overall how reliable this and other tests may actually be.

Suspected DUI Offenders & Field Sobriety Tests

The primary reason that the walk and turn test is used is that it requires divided attention. This means that the task requires the suspect to maintain attention on both mental and physical tasks which are exceedingly difficult at the point of intoxication. The walk and turn test was designed specifically to require the suspect to listen, remember, and properly execute instructions while engaging in physical movement.

The walk and turn are just one of the standardized field sobriety tests that have been established by the NHTSA, or National Highway Traffic Safety Administration. The tests are now considered standardized because they have been studied and backed up with statistical evidence over the years. It has been found that they have a strong correlation between test failure and impairment.

There is also the HGN test and the leg stand test. The HGN test is for the evaluation of horizontal gaze nystagmus, which is an involuntary movement of the eyes while following a point of focus along a horizontal plane in their field of vision. The leg stand test tests the subject’s balance while answering questions.

The walk and turn is considered the second most reliable test that the NHTSA has sanctioned. The HGN test is often seen as the most reliable since nystagmus cannot be easily controlled. The leg stand test is seen as the least reliable of the three standardized field sobriety tests.

Instructions for the Walk and Turn Test

The National Highway Traffic Safety Administration has outlined a set of standardized instructions for law enforcement to be equipped to correctly and competently administer the walk and turn test. The steps are as follows:

  1. Have the suspect stand heel-to-toe during the instructions.
  2. Demonstrate placing your left foot on the line.
  3. Demonstrate placing your right foot on the line ahead of the left foot, with the heel of the right against the toe of the left.
  4. Demonstrate placing and keeping arms down at your sides.
  5. Advise the suspect to maintain this position until the end of the instructions and the test begins.
  6. Verify that the suspect understands the instructions.
  7. Advise the suspect that when they are told to start, they are to take 9 heel-to-toe steps, then turn, and take 9 heel-to-toe steps back.
  8. Demonstrate how to pivot on one foot while taking small steps with the other to effect the turn.
  9. Advise the suspect that while they walk they are to keep their arms at their sides, watch their feet, and count the steps out loud. 
  10.  Advise the suspect that once they start walking they are not to stop until finished.
  11. Verify once more that the suspect understands.
  12. Advise the suspect to begin, counting from the first heel-to-toe as “one”.

What the Officer is Looking for During a Walk and Turn

The walk and turn test is intended to be most effective with drivers suspected of having a BAC of 0.10% or greater. This level of intoxication will often create a series of scorable mistakes. These clues are each worth 1 point, with the exception of a failure to finish, which is worth 9 points. A suspect only needs 2 points to be classified by the law enforcement agent as DUI.

Each clue will have acceptable and unacceptable variances. Those that are acceptable should not be scored, while those that are over the threshold of acceptance should be scored.

  • Unable to Maintain Balance During Instructions

Scoring this clue occurs if the suspect is unable or unwilling to maintain the heel-to-toe posture for the duration of the instructions. The officer should not consider this a score if the suspect uses arm movement for balance, or sways but stays in position.

  • Begins Before Instructions Are Complete

The suspect gets a point for this clue if they begin the test before the officer’s instructions are complete.

  • Stops Walking to Regain Balance

Stopping for more than a second or two is considered a scorable event, however, the suspect should not be scored if they are simply walking slowly.

  • Fails to Touch Heel-To-Toe

One point is earned for this clue if the suspect is unable to meet the heel-to-toe requirement by leaving a gap of 0.5” or more on any step. This will also be scored for not walking straight along the line.

  • Leaves the Demarcation Line

If at any point the suspect leaves the line, they get a point. However, this item can only be scored once even if the mistake is made several times.

  • Use Arms to Balance

This point is scored if the arms raise more than 6” from the at-sides position to maintain balance. No exceptions.

  • Loses Balance During Turning

During the turn, if both feet leave the line it is scored. This will also be scored if the turn is not a multi-step pivot as detailed in the instructions, and is instead a one-movement turn.

  • Taking More or Less Than 9 Steps

This clue is scored if the suspect fails to take 9 steps.

  • Unable to Complete the Test

If the suspect leaves the line 3 or more times or falls, they have demonstrated a failure.

Appropriate Testing Conditions

The officers are legally required to ensure that the test is conducted in an area or location that allows the test to be completed in a fair and safe manner.


There should be adequate lighting, demonstrated by the suspect being able to see the officer and understand their directions and demonstrations.


The surface should be relatively flat, hard, level, and non-slip. There should be enough room to take the required steps, and there should be no danger of falling or tripping.


The test requires a line or other mark to follow. If there are no lines in the road, the officer may draw one with chalk, draw in the dirt with a stick, or may use a parallel walk along a curb if needed.

Reliability of Field Sobriety Tests Like the Walk and Turn

There are many factors that can impact the effectiveness and accuracy of the walk and turn test, and the NHTSA data shows nearly one in three people fail who are not under the influence.

Impact Of Mental & Physical Impairments or Disabilities

Common reasons for lower reliability include elderly suspects or those who have problems with various parts of the body. There can also be issues with extremely small suspects or those who are obese, as these impairments along with countless others may cause clues to be scored inaccurately.

Surface Setting 

One of the most important criteria of the walk and turn test is the surface. If the officer does not conduct the test on a flat, level, dry, non-slip surface, the score and ultimate determination of the test are reduced to worthlessness.


The test should be conducted in an area where the suspect is able to concentrate and is not distracted by heavy traffic, close vehicles, excessive honking, or sirens. The officer is also supposed to be motionless during the test, and if they choose to walk around the suspect or interfere in any way then the test may be invalidated.

Problems With Clothing or Shoes

Sometimes clothing can prevent an issue to proper completion. High heels over 2” should be removed, and any restrictive or excessively baggy clothing may cause a failure as well.

Facing Charges Stemming From a Walk And Turn Test?

If you or someone you know was given a field sobriety test and subsequently faced DUI charges, it is imperative that you get in contact with an experienced, local law firm that can help keep your rights preserved. Reach out today to discuss the details of your case in a confidential environment, and build an attorney-client relationship that advocates for you.

Physical Disabilities That Can Be Mistaken for Intoxication

When a police officer stops someone under suspicion of driving under the influence (DUI), the officer watches the person for signs of intoxication. If the driver refuses to take a breathalyzer test, the only basis for a DUI arrest might be the police officer’s observations of signs of intoxication.

Signs of intoxication often cited by police officers when making a DUI arrest include:

  • An odor of alcohol emitting from the person or vehicle
  • Slurred speech
  • The person has trouble and fumbles when trying to take out their driver’s license and insurance information
  • Incoherent speech
  • Bloodshot or watery eyes
  • Poor driving behaviors, such as weaving, driving too slowly, using turn signals incorrectly, stopping at green lights, etc.
  • Falling over while standing up
  • Poor coordination and motor skills
  • Slow verbal responses when asked questions 
  • Telling different stories when answering questions 
  • Stumbling when exiting the vehicle
  • Disorientation or confusion 
  • Difficulty staying awake or holding up their head

If the police officer observes any of the above signs of intoxication, the officer will likely arrest the person for DUI and take them to jail. However, there could be other reasons a person displays the signs of intoxication. For example, physical disabilities and medical conditions may include some of the above symptoms. Therefore, a person with pre-existing medical conditions that cause signs that mimic intoxication could be unjustly arrested and detained. 

Medical Conditions and Physical Disabilities That Could Be Mistaken for Intoxication

Multiple physical disabilities and health conditions impact a person’s ability to walk a straight line, speak clearly, or maintain balance. As a result, the person may “fail” DUI field sobriety tests. Common physical disabilities and medical conditions that could cause a police officer to believe the person is intoxicated include, but are not limited to:

Traumatic Brain Injuries 

For some individuals, the symptoms of traumatic brain injuries remain for months or years after the brain injury. Some people may experience lifelong symptoms of brain injury. 

A person could experience speech, coordination, balance, and memory problems. While people who know the person are familiar with how the person normally behaves because of the brain injury, a police officer could mistakenly believe the person is intoxicated.

Degenerative and Neurological Disorders 

Numerous degenerative disorders impact a person’s coordination, speech, cognitive ability, and memory. During the early stages of these diseases, a person may be able to drive, but they could experience periods of heightened symptoms. 

Examples of neurological or degenerative disorders that could mimic intoxication include:

  • Dementia
  • Cerebral Palsy
  • Ataxia
  • Alzheimer’s disease
  • Multiple Sclerosis
  • Korsakoff syndrome
  • Huntington’s disease
  • Parkinson disease
  • Myasthenia Gravis

An undiagnosed brain tumor could cause a person to experience symptoms that mimic intoxication. Additionally, a person could have any one of numerous disorders or diseases that they are unaware of at the time of a DUI arrest. 


A person with diabetes may experience periods of extremely low blood sugar levels. When a person’s blood sugar level falls too low, the person could experience dizziness, disorientation, slurred speech, and irritability. A police officer could mistake these symptoms as intoxication.

Additionally, a person with diabetes may have extremely high levels of ketones in their breath. High levels of ketones can cause a false positive on a breath test.


A person with epilepsy may experience a seizure without warning. Epilepsy may not always cause seizures. A person may appear to be confused, have trouble speaking, be unsteady on their feet, or have trouble focusing. A police officer who stops a person who is experiencing a seizure or just experienced a seizure might believe the person is drunk.

How Could a Medical Condition or Physical Disability Cause You to Fail a DUI Field Sobriety Test?

It may be difficult to believe that a police officer could mistake a person’s medical condition for intoxication. However, standardized and non-standardized field sobriety tests measure a person’s cognitive and physical abilities. Because many physical disabilities, illnesses, and health conditions impair physical and cognitive abilities, a police officer may not be able to distinguish between intoxication and a medical condition.

The standardized field sobriety tests approved by the NHTSA (National Highway Traffic Safety Administration) are:

  • One-leg stand test
  • Walk and turn test
  • Horizontal Gaze Nystagmus (HGN) test

In addition to the standardized field sobriety tests, many police officers use unofficial field sobriety tests to look for signs of intoxication. Some of those tests include, but might not be limited to:

  • Finger-to-nose test 
  • Rhomberg balance test
  • Hand pat test
  • Finger count test

Field sobriety tests measure your ability to perform specific tasks. While you perform the tasks, the police officer looks for signs that you are intoxicated. However, many of these tasks are the same tasks that could be impaired or affected by an illness or medical condition. Therefore, your inability to perform the tasks might stem from your health condition, instead of alcohol. 

Things that a police officer looks for when administering field sobriety tests include:

  • Involuntary tremors and muscle tone that is too limp or overly rigid
  • Inability to follow instructions or follow a set of instructions in the correct order
  • Performing tasks very slowly
  • Making inappropriate or confusing comments
  • Inability to stand still
  • Swaying back and forth
  • Being unsteady on your feet and stumbling
  • Slurring your words and having difficulty translating thoughts into spoken words

The issue is that these “clues” of intoxication can be caused by numerous health conditions. Therefore, the field sobriety tests are inaccurate and invalid. However, a police officer has no way of knowing this fact during a DUI investigation on the side of the road. To the police officer, the person appears intoxicated. Therefore, the officer arrests the person for driving under the influence without conducting any further investigation.

Health Conditions Can Affect a Breathalyzer Test

In addition to affecting field sobriety tests, some health conditions could affect a breathalyzer test. These conditions could result in a “false positive” on a DUI breath test even though the person does not have any alcohol in their system.

Health conditions that could impact a breathalyzer test include:

Digestive Disorders

Digestive disorders such as acid reflux, hiatal hernia, heartburn, Gut fermentation syndrome (auto-brewery syndrome), and GERD (gastroesophageal reflux disease) can “trick” the breathalyzer into thinking that you are intoxicated. Instead of picking up residual mouth alcohol from deep lung air, the test detects stomach contents that flowed back up into the esophagus. 

Conditions That Affect Blood Sugar

Several conditions that affect blood sugar can cause incorrect breathalyzer results. Conditions include diabetes, high-protein diets, hypoglycemia, and fasting. 

Carbohydrates in the food we eat break down into sugars, including glucose. Glucose is the primary energy source our bodies use. However, if we do not eat enough carbohydrates to produce the glucose our bodies need, our bodies use fat stores for energy.

The fat is broken down into chemicals, including isopropyl alcohol and ketones. Excess ketones and isopropyl alcohol exit the body through your breath and urine. People with diabetes or hypoglycemia can also have high levels of ketones. 

Even though breathalyzer manufacturers claim that their machines can differentiate ethyl alcohol found in alcoholic beverages and isopropyl alcohol, people with excess ketones can receive false “positives” on breathalyzer tests.


Some medications can affect the results of a breathalyzer test. If you take these medications for a health condition, the results of a breathalyzer test could indicate you are intoxicated even though you have not consumed any alcohol.

Medications that could give a false “positive” on a breathalyzer test include:

  • Asthma inhalers can dispense large amounts of alcohol in the lungs
  • Cough and cold medications that contain alcohol 
  • Medications to relieve pain from cold sores, toothaches, and canker sores often contain high amounts of alcohol

If a breathalyzer test or other chemical test shows you have a high blood alcohol content (BAC) when you did not consume alcohol, you should contact a DUI defense lawyer immediately to challenge the results. 

What Should You Do if You Have a Medical Condition That Could Be Misinterpreted as Intoxication?

Wearing a medical alert bracelet or necklace that notifies officers of your medical condition could be helpful during a DUI stop. Notify the officer of your medical condition and request medical assistance. If you begin to experience symptoms that impair your ability to drive or feel unwell, pull over to a safe location and call 911. 

Even though you tell a police officer you have a medical condition that could be causing symptoms that mimic intoxication, the officer may still arrest you for driving under the influence. Do not resist arrest as that could result in additional charges. Instead, when you arrive at the jail, make another request for medical attention. Also, invoke your right to remain silent and request to speak with an attorney.

With an attorney’s assistance, you can fight the DUI charges. Your attorney helps you develop a defense based on your medical records, expert opinions, research, witness statements, and scientific evidence. A DUI arrest is not a conviction. If you have a medical condition or physical disability, do not plead guilty to a DUI charge without consulting a DUI defense attorney.