Recent Blog Posts

FST Pseudo-Science, Part I

DUI Defense Lawyer — Wed, 12 Jan 2011 15:20:00 GMT

Pseudoscience means "a discipline or approach that pretends to be or has a resemblance to science, but is based on false assumptions." Examples include astrology, psychokinesis, clairvoyance and field sobriety testing.

In a DUI trial, one of the most important parts of the evidence is known as the Field Sobriety Tests or FST's. In a previous blog, I told you that you should never perform these tests. One of the main reasons for that is just how little scientific relevance these tests have. Oh, where to begin?

The National Highway Transportation Safety Administration (NHTSA) developed the "Standardized Field Sobriety Tests" (SFST's) over a series of studies done between 1975 and 2004. NHTSA claims these studies revealed that by using three Field Sobriety Tests (the SFST's), police officers were able to discern drivers who were over the legal Blood Alcohol Content (BAC) with 78% accuracy. Through a trick of semantics, NHTSA now claims that in one study (the "San Diego Study") they were 91% accurate!

Nonsense.

Here's how you perform a proper study to validate tests: Have trained police officers do the FST's for a bunch of people, then note how often the officer is right. Then tell people the result. End of story. But that's not what NHTSA did.

Instead, NHTSA had trained police officers perform the FSTs on hundreds of drivers. But they also assessed those drivers in other ways. They interviewed them. They smelled their breath. They looked for physical evidence like open bottles. They got confessions. AND they gave a portable breath test (PBT) to every driver. THEN the officers wrote down their guess for the driver's BAC. It's patently ridiculous to claim that this was a valid test of the Field Sobriety Tests.

But wait, there's more.

FST's are not supposed to predict a particular BAC, only to indicate if they are high or low. These tests were highly accurate only if you look at how many high-BAC drivers were arrested. Nearly all of them, in fact (giving rise to that 91% figure). But they also indicated that nearly all the low-BAC drivers had a high BAC. In fact, the FSTs were only 30% accurate in identifying innocent people. That is, when the government bags nearly as many innocent drivers as it does the guilty, it declares success.

Would you fly on an airline that landed safely 91% of the time? What about 30% of the time?

One more thing. That 30% relied solely on one officer. Six of the seven officers were wrong with 100% of the innocent drivers (that is, even after the interview, the FST's and the PBT, they identified every innocent driver as being over the limit).

Only one of the seven officers was ever correct about the innocent drivers, and he was correct about those innocent drivers 100% of the time. When the FST's were wrong, his estimates were right anyway. How did he do it? Well, I wasn't there. But I'll just say that his estimates exactly matched those measured by the PBT every time.

Once again, YOU DO NOT HAVE TO PERFORM FIELD SOBRIETY TESTS. Don't. Just politely tell the officer you won't do them.

PS: I am NOT saying the police officers did anything wrong. They did what they were supposed to do. I am saying that the data was reported in a deliberately misleading fashion and are used every day to prosecute innocent people.

Breathalyzer Lies

DUI Defense Lawyer — Thu, 28 Oct 2010 18:07:00 GMT

One of the main tools police use in proving their case is a hand-held breath-testing device often called a “breathalyzer” and also known as a Preliminary Breath Test or Roadside Breath Test. After the badge and the gun, this is one of the most-recognized police devices. But few people understand how many half-truths and outright lies surround its use.

Several models of Preliminary Breath Test (PBT) are used in Virginia. All use an electro-chemical fuel cell that passes a current through two platinum electrodes, one of which will have oxidized any alcohol in your breath. Comparing the difference in the current results in a number that is supposed to reflect your Breath-Alcohol Concentration (BAC).

The first (and worst) lie that many people are told about this device by the police is “this test can’t be used against you in court.” What a surprise, then, that the test is mentioned in every DUI trial. In fact, it would be more legally accurate for the officer to say “this test can’t be used against you in a prosecution.” This is what the law says. But even that is misleading. According to the Virginia Supreme Court, not every aspect of your trial is a “prosecution”. Funny, but when you’re on trial and you might go to jail, it all feels a lot like a prosecution. The PBT can and will be used at trial to show that the officer had the authority to arrest you.

Manufacturers and law enforcement like to discuss the accuracy of these devices, but they can produce a host of “false positives” and “false negatives”, meaning that they can indicate sober people are drunk and vice-versa.

The computer inside the PBT multiplies the amount of alcohol detected by 2100. This is because it is assumed that the average individual has a ratio of 2100 units of alcohol in his blood for every one in his breath. This is known as the “partition ratio”. In fact, the true amount varies widely from individual to individual, from as low as 900:1 to as high as 3500:1. If your partition ratio isn’t exactly 2100:1, the reading will be falsely high or low. Thus a person with a measured BAC of 0.08 might actually have a true BAC anywhere from 0.034 to 0.133. And that’s just plain unfair.

Manufacturers also claim the PBT is “specific for alcohol”. However, the human body produces alcohol naturally. Eat a slice of white bread, chew it slowly, taking a minute or so. Then blow into a PBT. You will have alcohol on your breath. As much as a 0.04. It also works with soy sauce and a vast variety of other foods.

Manufacturers also claim that is necessary to blow hard into the PBT to get an accurate result. They claim that something they call “deep lung air” gives the most accurate results. In fact, blowing harder simply produces a higher result. “The more you blow, the higher you go,” is a phrase often heard in breath testing.

Finally, there is an assumption that your breath has come solely from your lungs. But individuals who suffer from Gastroesophageal reflux disease (GERD) (also known as acid reflux) and have any alcohol in their stomachs may be emitting that alcohol directly into their throats, where it coats the mucus membranes of the mouth and sinuses and can give a falsely high reading as much as 150% of the true BAC. Thus, a person suffering from GERD who has a measured BAC of 0.10 might actually have a BAC as low as 0.66. Even assuming a partition ratio of exactly 2100:1.

Remember, this test and all the other roadside tests are voluntary. You do not have to take it and you should not take it. Ever.

DON’T PERFORM FIELD SOBRIETY TESTS

DUI Defense Lawyer — Sun, 26 Sep 2010 07:19:00 GMT

A motorist suspected by the police of driving under the influence of drugs or alcohol will be requested to perform a series of field sobriety tests. All drivers should understand that these tests are VOLUNTARY. That means you don’t have to do them. YOU SHOULD NEVER DO THESE FIELD TESTS. Never. Not for any reason. Ever. Most especially not if you’re sober (because then you should know better).

The reason is that these tests are “designed to fail.” People don’t pass these tests, they only fail them. Police will tell you they use these tests to determine whether or not a driver is capable of driving safely. That’s not true. They use these tests to support their decision to arrest you; to create “probable cause”, in legal parlance. We know this is true because almost nobody who performs these tests is ever allowed to drive away afterwards. In short, no matter how well you think you did on these tests, you can only fail them.

It is your right to refuse these “tests”. Police officers may pressure you to take them, but they cannot force you to do so and it is not against the law to do so. Let me be clear: the police officer will arrest you for DUI and he will take you to jail. But that was going to happen anyway. If the police officer arrests you on insufficient evidence your case may be thrown out, but at the very least you will not have given the prosecution more evidence on which to convict you.

Virginia has no standards for how these so-called “tests” must be administered. In most states, officers are trained to perform a set of three Standardized Field Sobriety Tests set forth by the National Highway Transportation Safety Administration (NHTSA). While the evidence that these NHTSA tests have any scientific relationship to intoxication is sketchy to begin with, they are at least standardized, meaning they can logically be compared to something. Virginia police, on the other hand, are not required to administer any particular set of tests. Virginia police frequently administer tests that are intentionally harder than the standardized NHTSA tests.

Worse, most Virginia judges routinely permit police officers to testify about these “tests” without requiring the prosecution to prove they have any relationship to whether or not the defendant is sober.

Worst of all is the roadside breath test (sometimes called a preliminary breath test). This tests is also voluntary and YOU SHOULD NEVER BLOW INTO IT. This small hand-held device is notoriously unreliable. In fact it is so unreliable that Virginia law does not permit the numerical result of the test to be used in a prosecution. Virginia police routinely tell defendants that the preliminary breath test “can’t be used against you in court”. This is (let’s not sugar-coat it) an out-and-out lie. The roadside breath test (and under certain circumstances, its numerical result) can and will be used against you in court. Don’t blow into it.

Welcome to our Fairfax DUI Blog

Fairfax DUI Defense Attorney — Sat, 18 Sep 2010 00:54:00 GMT

We are pleased to announce the launch of our Fairfax DUI Blog.