Field Sobriety Test vs. Breathalyzer: Differences Explained Simply

Understanding the difference between a field sobriety test vs. a breathalyzer can help you protect your rights. A field sobriety test is something that officers may administer when they pull you over because they think you’re under the influence of drugs or alcohol. For example, they might ask you to say the alphabet backward or stand on one leg. 

A breathalyzer is a machine you blow into and receive an estimate of how much alcohol might be in your system. A breathalyzer is one of the many tools the cops may use in a sobriety test. However, these field tests are known for being inaccurate. Because of this, blowing over the legal limit or failing other sobriety tests doesn’t necessarily mean the cops have sufficient evidence to arrest or convict you.

When the cops arrest you for a DUI, it’s imperative to take proactive steps to protect your rights and set up a solid defense. At Veitch Ault Defense, our King County DUI attorney has fought for the accused for over 20 years. We have the tools to comb through the record and find flaws in the field sobriety or breathalyzer test the cop used to arrest you in the first place. We can’t promise a particular outcome, but we can put in the work to help reduce or dismiss the charges against you.

Is a Field Sobriety Test the Same as a Breathalyzer?

A field sobriety test refers to a range of tools cops use to figure out if you are under the influence of drugs or alcohol. For example, the cops may observe your behavior to see if you slur your words or can’t stand up straight. Likewise, they may have you try to walk in a straight line or bend down and pick something up. 

If you fail these tests, the cops may take it further and ask you to take a breathalyzer. A breathalyzer is a small machine that you blow into. It measures how much alcohol is in your breath and uses that to calculate your blood alcohol concentration or BAC. 

If you refuse the breathalyzer or you blow over a certain level, the cops may use this to justify officially arresting you. Under Washington Law, the government can use several different tests to measure the amount of alcohol or drugs in your system. For example, they can have you take a blood or urine test to see how much alcohol or THC you have in your body. When the cops arrest you and take you to the station to be booked, they may ask (or require) you to participate in these other tests. 

Why Do Police Use Field Sobriety Tests Instead of a Breathalyzer?

The cops use field sobriety tests to get an informal and preliminary idea of how intoxicated they think you are. They may start with unscientific measurements—e.g., how you’re walking or talking—to form the reasonable suspicion needed to ask you to submit to other tests. For example, if you slur your words or smell like alcohol, police may use this information to move on to a breathalyzer. If this leads to an arrest, they may ask you to give a blood or urine sample at the station. 

Is It Better To Do a Breathalyzer or Blood Test?

Using a breathalyzer to measure your BAC levels can yield inconclusive and inaccurate results. Because the cops administer these tests in the field, there aren’t as many safeguards to ensure accuracy. For example, the person may not blow into the machine properly, leading to a much higher result than what it should be. As a Washington DUI attorney can attest, even a simple oversight in the breathalyzer’s calibration can undermine the credibility of the results. 

In contrast, a blood test is more likely to give an accurate result. Drawing and testing the blood is more scientific and measured. Even so, the people administering the blood test may make mistakes. For example, if the technicians don’t store the blood properly, contamination may lead to a higher BAC. Regardless of how the cops measure your BAC, you or your attorney may have ways to challenge the evidence against you.

Should I Take a Breathalyzer if I’m Sober?

Many people may think refusing a breathalyzer is a good idea if they’re confident that they’re sober. They may believe that not taking this test limits the chance of them being charged with a DUI. However, refusing a breathalyzer may pose more problems for you than it prevents. 

Washington law penalizes people for refusing a breathalyzer or other type of sobriety test if the cops have reasonable suspicion that they have been drinking. For example, they may take away your license for at least a year and use other evidence against you in court, including your refusal.

Additionally, the police may still be able to arrest you and use other alcohol testing devices at the station. Unfortunately, this may mean that the police get more reliable evidence—e.g., the blood test—to charge you with a DUI. All in all, in some situations, it may be in your best interest to take the breathalyzer. You still have the option to challenge the test results on other grounds during the trial. 

Veitch Ault Defense: We Can Help You Challenge the Legality of Your Sobriety Test

When the cops pull you over for a DUI, they may use a number of sobriety tests to measure your BAC. If these results come back as over the limit, you may worry about what this means for your ability to defend yourself against the charges. Fortunately, there may be ways to challenge the results and, hopefully, get these charges thrown out. 

Veitch Ault Defense truly cares about fighting for your rights and helping you get your life back on track. Robert J. Ault is a leader in this field and has multiple certifications in administering field sobriety tests. He uses his incredible knowledge of chemical testing and the law to his client’s advantage. Past clients praise his unwavering support and compassion and his ability to comfort and guide them through the court proceedings. When you’re arrested for a DUI based on a flawed sobriety test, contact us by calling 425-549-9547 to set up a free, no-obligation consultation.


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