Oregon DUI Lawyer Blog

The limitations to Field Sobriety Tests are making some national news. ABC news recently ran a report about a man who was found not guilty of DUI because he was obese. The report strongly implies that the man somehow got out of a drunk driving charge based on some sort of novel defense.

This report indicates that the field sobriety tests which the man took were published by the National Highway Traffic Safety Administration. What the report fails to say is that NHTSA itself says field sobriety tests are not effective for overweight people. According to the 2006 SFST Student Manual, people who are more than 50 pounds over weight have trouble performing the test.

As I have pointed out earlier, FSTs are correlated to specific breath alcohol concentrations. This means that performance on FSTs merely indicates a probability that an individual has a certain breath alcohol concentration. NHTSA admits that there is no way to measure one's ability to drive through the use of FSTs.

The way FSTs are designed to draw this correlation is through standardization. When done properly, the FSTs are administered exactly the same every time. The officer conducting the tests looks for exactly the same clues every time. When everything is as standardized as possible, NHTSA claims inferences about a correlation to breath alcohol can be draw.

When standardization is not followed, however, no inferences can be drawn. Also in the student manual, NHTSA says in bold capital lettering that if any one of the standards is changed the validity of the test is compromised. That isn't some slick DUI defense attorney talking. That is NHTSA itself.

With this in mind, it makes sense why the FSTs are ineffective for overweight people. People who have more trouble than average doing the test cannot be measured in a standard way. Without a standard measure, the test is compromised.

It is nice to see the limitations of the FSTs getting some attention. It would be nicer if the coverage pointed out the true reason for the limitations.

In Oregon, and everywhere else I've been, prosecutors and police love roadside agility tests, which they call Field Sobriety Tests. I have already discussed why you should not take these tests. Even if your refusal to take the tests is used against you in Court, it is still better than these unfair tests.

Today I will discuss why the results of FSTs should be considered irrelevant in cases without a BAC. Contrary to popular beliefs, including the beliefs of most prosecutors, cops, and judges, the FSTs are not designed to detect impairment. They are only designed to show a probable correlation with a breath test result.

The Godmother of FSTs is Marcelline Burns of the Sothern California Research Institute. Although Dr. Burns has been preoccupied with trying to show the effectiveness of FSTs for decades, even she admits that roadside tests cannot show impairment. In a 1998 paper entitled, Validation Of The Standardized Field Sobriety Tests Battery At BACs Below 0.10. U.S. Department of Transportation, National Highway Traffic Safety Administration, DOT-HS808-839 (1998), Burns admitted, "It is unlikely that the complex human performance, such as that required to safely drive a car, can be measured at roadside."

This is an astounding statement from the government's leading FSTs researcher. Burns went on to say that the goal of FSTs is to "provide statistically valid and reliable indication of a driver's BAC rather than indications of driving impairment." Burns fully admits "SFSTs do not directly measure driving impairment."

These statements are useful in any case involving roadside tests. The government should never be allowed to say that the tests show anything about an accused's ability to drive. These statements should be even more powerful in cases in which there is no breath test result.

Because FSTs show nothing about someone's ability to drive, they are not probative of anything other then correlation to a BAC. If there is no BAC admitted into evidence, for what purpose can the FSTs be admitted?

There are two basic types of DUI cases that don't have breath test results. The first is a refusal case, where the accused did not take the breath test. The second is a case in which the accused did take the test, but a skilled DUI lawyer got the test suppressed. The analysis above regarding the relevance of FSTs should apply equally to both cases. Judges, being human, are likely to treat the two differently however.

In any event, this type of argument should be raised in all cases in which there are FSTs but no BAC. The best way to change erroneous popular beliefs is to continue pointing to the truth. The truth is FSTs cannot detect impairment.

Alexa Kerry, Senator John Kerry's daughter, was arrested for DUI last night. According to news reports, Ms. Kerry was given field sobriety tests before she was arrested. Ultimately she had a breath alcohol concentration (BAC) of .06.

These results show how unreliable the FSTs can be. As in Oregon, the presumptive limit in California is .08. After giving Ms. Kerry the field sobriety tests, the police apparently believed that Ms. Kerry was under the influence. Otherwise there would be no basis for an arrest.

This case shows one of the fundamental problems with field sobriety tests. Field sobriety tests are standardized and lab certified. Prosecutors routinely argue that performance on field sobriety tests should be used as the basis for criminal convictions for DUI. However, FSTs are designed to look for a correlation to a BAC not to look for intoxication.

Field sobriety tests are certified by the National Highway Safety Administration. During lab certification, subjects are dosed with a quantity of alcohol. Then testers are asked to administer the FSTs to the subjects. Testers then attempt to identify those subjects who are intoxicated. The testers are not told how much alcohol the various subjects have consumed. According to these lab certifications, the FSTs are accurate at .10. Meaning, that if the standards are followed, the tester should be able to identify someone was a BAC of .10 using the FSTs.

The problem with this lab certification is that it is based on statistics. The certification is essentially saying that there is a statistical correlation between certain performances on the FSTs and a certain BAC. As a matter of scientific research, such a correlation may be interesting for a variety of reasons. As the basis for a criminal prosecution, however, it is frightening.

Ms. Kerry's case demonstrates that police can and do arrest people who have BACs well under .10 even after administering the FSTs. In such cases, prosecutors often attempt to argue that the performance on the FSTs shows intoxication despite the low BAC. This argument fails to understand the presence of outliers.

Field sobriety tests are not designed or certified to show intoxication. They are only certified to show a correlation with a specific BAC. When someone like Ms. Kerry fails the FTS but has a low BAC, she is a statistical outlier. This result says nothing about Ms. Kerry's level of intoxication. It only shows that the FSTs are not perfectly correlated to BAC.

One question I get a lot as a DUI lawyer is what to do if pulled over for DUI in Oregon? Most people want to know whether or not they should take the roadside tests and whether or not to take the breath test. In the post, I will address the roadside tests.

Roadside tests are often called standardized field sobriety tests or FSTs. These tests are designed by the National Highway Traffic Safety Administration (NHTSA). There are three parts the tests: the HGN, the walk and turn, and the one leg stand. Some arresting officers at a DUI stop throw in a few other tests as well. But those other tests are not standardized.

The first phase of the standardized test is the horizontal gaze nystagmus test or HGN. This is the test where the arresting officer passes a pen in front of the subject's eyes. The test is designed to look for a jerking of the eyes called nystagmus. In order to be valid, the office must follow a very precise protocol. Many officers cannot explain these protocols when questioned by an experienced DUI attorney.

Consuming alcohol does cause horizontal gaze nystagmus in most people. Because of that fact, police and prosecutors love to point to the HGN test as evidence that someone was drinking. What police and prosecutors often fail to mention is that there are many types of nystagmus. Simply observing eye jerking does not prove the source of that jerking.

Moreover, laboratory studies have found HGN in people with breath alcohol concentrations as low as .04. This level is half the presumptive limit in Oregon. Basically, the HGN is a worthless test that proves nothing more than that a person may have drank half the legal limit.

The second test in the FSTs is the walk and turn. In this test, someone is asked to walk heel-to-toe along a line. Often an office asked someone to just imagine a straight line if there isn't one on the ground already.

Most people who take this test think they are just being tested on whether or not they can walk heel to toe. The cop is really looking to see how well someone can follow complicated directions. It is considered failing if someone doesn't take the exact right number of steps, if they don't make a special type of turn, or if they don't bring their heels within an inch of their toes. This test is inherently unfair because people are never told what they are actually being tested on.

The last test is the one leg stand test. In this test the person is asked to stand on one foot for thirty seconds. Again, the cop never tells the person that he is actually looking for the way he stands, whether he looks at his foot, or how well he estimates 30 seconds.

None of these tests are fair. They are designed to fail. You should not take these test even if you have had nothing to drink. If you are asked to take these tests, you should politely refuse. If you are arrested, immediately ask to speak with a qualified DUI lawyer.