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Wisconsin Drunk Driving Tests

Standardized FSTS | BAC Chemical Tests | WI Blood Alcohol Limits | Refusal

about blood tests

Standardized Field Sobriety Tests

Standardized field sobriety tests are tests administered by police officers "in the field" when they stop a person suspected of drunk driving. Those tests include:

• Standing on one leg for up to 30 seconds,
• Walk and turn, sometimes administered as heel-to-toe
• Horizontal gaze nystagmus, which may also include vertical gaze nystagmus (the suspect is asked to follow the movement of a penlight)

While the term "in the field" conjures up a vision of a police officer pulling a car over to the side of the highway, the reality is that the stop can occur just about anywhere including in a person's driveway or in a parking lot, with the car or truck running or idle. Just because a police officer stops a person does not mean that the stop was legal, even if the person was arrested. There are many technicalities in drunk driving law, which a highly experienced drunk driving defense attorney immediately recognizes. Regardless of the situation, if you were arrested for drunk driving, you should consult with a DUI defense attorney.

Blood Alcohol Concentration Level Testing

A person's BAC (Blood Alcohol Concentration) level is determined by testing. The results of those tests are used to support the prosecution of drunk driving cases.

Intoximeter - Breathalyzer

The Intoximeter, or breathalyzer, is a breath test machine designed to measure the percentage of alcohol in the bloodstream of the suspected drunk driver. The results are used to determine if the person is intoxicated. The Intoximeter EC/IR is conducted at the police station.

Intoximeters require a suspect to blow into a machine. The air passing through the machine is measured for alcohol levels. Administers (usually police officers) are trained and certified in the usage of Intoximeters; even so, tests may be administered incorrectly, Intoximeters may be miscalibrated, or results may be recorded incorrectly. Your drunk driving defense attorney will know what questions to ask and how to determine if any of these situations existed at the time of your arrest.

Do I have to take a breath test?

In Wisconsin, the law provides for immediate suspension of your driving privileges if you refuse to submit to a test.

A breath analyzer test measures a person's BAC or BAL. The amount of ethanol that is in your system is the same as the amount of ethanol that is "on" your breath when you exhale and inhale. As a result, police are able to test your BAC or BAL by having you breathe into a breath analyzer.

Why breath tests aren't always accurate and believable.

Breath tests shouldn't be treated as gospel. They aren't always accurate.

Some breath tests can't be used as evidence at trial. The so-called "preliminary breath test," or "PBT" -- the portable test used by police at the scene -- can't be used as evidence at trial. Wisconsin's statutes don't permit it.

All breath test machines, including the ones the State uses as evidence in court (usually an Intoximeter EC/IR machine), can give inaccurate results.

There are lots of reasons. All breath test devices are susceptible to "sampling error." A breath test machine doesn't really test your breath. It tests only a very small part of your breath: generally, only 81 cubic centimeters. Then it states the results in terms that disguise the fact that only very small sample of breath, with an infinitesimal alcohol content, has been analyzed. The result can be accurate only if the sample is actually representative of the alcohol concentration in breath from the lowest part of your lung. But it may not be representative of the lower lung air because the act of blowing into the machine requires the breath to pass through the bronchial tree and mouth. Alcohol can be added to the breath from these sources, giving a falsely high reading when the exhaled breath is sampled and tested.

Though machines report test results in terms of 210 liters -- roughly the volume of a 55 gallon oil drum -- they actually only test 81 cubic centimeters of breath -- about the volume of a bathroom size paper cup. In that sample, it takes only about a millionth of an ounce of alcohol in the breath sample -- 0.0000013 oz. -- to get a 0.10 reading. So, even the slightest extra amount of alcohol added to the sample as it is exhaled will give enormously exaggerated results.

Additionally, the Intoximeter EC/IR used for many breath tests in Wisconsin can have engineering and operating defects which make it vulnerable to "radio frequency interference" from police radios and from cellular telephones. Also, the Intoximeter may have been operated with the "slope detector" function -- a safeguard designed into the machine to prevent testing a breath sample contaminated by alcohol from the mouth -- disabled by the Department of Transportation. (There is more information about the Intoximeter EC/IR in the FAQ right below this one.)

Then, too, some police officers administer breath tests improperly. A breath test should never be administered until after the test subject has been continuously observed for at least twenty minutes immediately prior to the test, to assure that there has been no burp or regurgitation which could have introduced alcohol into the mouth. Some officers ignore the twenty minute rule, and most don't bother to watch the test subject closely. Instead, they just wait out the time by doing paperwork associated with the arrest.

A test result shouldn't be believed merely because it was obtained on a machine used by the police. Police officers believe that breath test machines are infallible. The truth is that even police officers trained in the use of these machines are utterly ignorant about how they work. The cop may be willing to take the accuracy of these tests on faith. You shouldn't be.

You should also check the next topic: What is wrong with the Intoximeter EC/IR breath test.

What is wrong with the breath tester?

Apparently a lot.

Wisconsin has purchased new breath testing machines. These are the Intoximeter EC/IR machines and they replace the Intoxilyzer 5000 in use up in Wisconsin as recently as last year. (Wisconsin doesn't use the "Breathalyzer," and hasn't since the 1970's.)

The Intoximeter EC/IR uses a fuel cell to measure alcohol concentration by converting it to water and electricity.

Recently an official of the Chemical Test Section, Wisconsin State Patrol, Department of Transportation, testified under oath that the Intoximeter EC/IR approved for use in Wisconsin was, in fact, not adequately shielded against "radio frequency" interference. As a result, many machines were taken out of service and installation of others was delayed.

"Radio frequency interference" is a common phenomenon -- it's what opens garage doors when, it seems, no one is around. Cellular phones and police radios create radio waves and can cause "RFI."

Even though the State discovered in 1999 that the Intoximeter EC/IR was vulnerable to "radio frequency interference," it did not change its standards for approval of the machines and has refused to disclose testing which it had privately performed after the manufacturer revised the machines.

The decision by Susan Hackworthy, Chief of the Chemical Test Section, to refuse disclosure of this test data, despite requests for the data under the Wisconsin Open Records Law, makes sense only if the data would embarrass the State. If the tests proved that the machine worker properly, both the State and the manufacturer would want the world to know.

The Department of Transportation is now warning police agencies not to operate cellular phones in the same room as an Intoximeter EC/IR, but there is no reason to believe this is an adequate measure to assure that "RFI," from cellular phones or other sources, is not affecting test results.

The problems, however, don't end with "RFI."

Inspection of these machines has revealed that the "slope detector" function has been disabled. This cannot be done by the machine operator. It can only be done by an official from the Chemical Test Section, because the settings of the machine, including the slope detector setting, are password protected.

The "slope detector" is the "IR" part of the machine. The "EC" in Intoximeter EC/IR stands for 'electro-chemical,' i.e., the fuel cell. This is the part of the machine that actually measures the purported alcohol concentration. The "IR" stands for 'infra-red,' and refers to measuring the absorption of infra-red light by the breath sample as it is blown into the machine. This is the "slope detector" function.

This slope detector function, the measurement of the alcohol in the breath sample as it is submitted to the machine, is designed to isolate contaminated breath samples by aborting a test if the alcohol level being blown into the machine exhibits a sudden spike in alcohol level. A spike in alcohol concentration would indicate "residual mouth alcohol" or another source of sample contamination. Disabling the slope detector eliminates the primary design defense of the machine against testing breath samples contaminated with extra alcohol.

If an Intoximeter test is administered on a machine with the "slope detector" operative, the results of testing may not be admissible in evidence in court. Wisconsin law generally allows only machines which are properly operating to be used as courtroom evidence in drunk driving cases.

More information about the Intoximeter EC/IR can be found at the breath test defenses.

Chemical Testing - Blood & Urine Tests

Chemical testing includes blood testing and urine testing, and either one or both tests may be administered by hospital personnel.

Blood tests require blood samples drawn from the suspects body (usually from a vein in the person's arm).

Urine tests require the suspect to provide a urine sample. Those samples are delivered into a container while the suspect is in a closely monitored bathroom facility. The water into the bathroom is shut off before the suspect enters the bathroom area, and the door is usually locked so that the suspect cannot leave the area.

As with all tests, the administrators must be properly trained in administering that particular test and must record the information correctly.

1st, 2nd, 3rd Drunk Driving Offenses

Under Wisconsin law, a person who is at least 21 years of age and without prior drunk driving convictions may not legally operate a vehicle with a blood alcohol level of .08 or above. However, if the person has prior convictions, the legal BAC level is lower. [Refer to Wisconsin Drunk Driving Law]

If the driver is under the age of 21 years, then under Wisconsin zero tolerance law, any trace of alcohol is illegal. (The legal drinking age in Wisconsin is 21 years).

4th & 5th OWI Offenses Subject to .02 BAC

If a person has been previously convicted of 3 or more drunk driving offenses, then the legal BAC level is .02.

Drunk Driving Defense Lawyer

If you have been arrested for drunk driving, you must act quickly to save your driver's license. Please call an attorney at Van Wagner & Wood right away for a brief, but professional free "first-impression" analysis of your drunk driving arrest and information about what you can and what you must do to preserve your rights and privileges under Wisconsin law. Attorney Tracey Wood is Wisconsin's foremost authority and expert advisor on drunk driving law and the only Wisconsin attorney ever appointed to the board for the National College for DUI Defense.

If you have already been convicted of drunk driving, you may have post-conviction remedies available to you that are often times missed by attorneys who are unfamiliar with prior drunk driving conviction challenges and appeals.

Call 608-284-1200 in Madison, or 1-866-262-4599 statewide

Related Topics:
Attorney Tracey A Wood | Drunk Driving
BAC - How To Determine Your Blood Alcohol Level
Challenging Prior Convictions | Felony Drunk Driving
Prior Convictions | How Drunk Driving Law Works
Save Your Driver's License | Wisconsin Drunk Driving Laws