Police often use various tests on drivers accused of drunk driving to measure impairment, from field sobriety tests to blood tests. As such, people might think a DUI charge is an open-and-shut case. It’s not.
There are a lot of variables when it comes to impairment tests, which can affect the charges.
What tests measure impairment?
People accused of drunk driving are usually given a series of tests. The following are tests commonly used by law enforcement officers:
- Field sobriety tests are tests used by a police officer on the roadside to determine probable cause for a drunk driving arrest. Standard tests include the horizontal gaze nystagmus test, the walk-and-turn test and the stand-on-one-leg test.
- Breath tests, often referred to as a Breathalyzer test, require the driver blows into a device that estimates the concentration of alcohol in the blood.
- Blood tests are drawn at a hospital or clinic after an arrest. They, too, determine the blood alcohol concentration in the individual tested. Blood tests are the most accurate measure of BAC.
- Urine tests measure the concentration of alcohol in the urine to determine BAC. They are the least accurate test and used less often.
Tests can be inaccurate
All tests for alcohol impairment have a chance for inaccuracy.
A driver may fail field sobriety tests for a multitude of reasons not related to impairment. There is no field test that can show for certain that a person is drunk.
Breath tests rely both on the accuracy of the equipment and the knowledgeability of the person administering the test. If the device is improperly calibrated, the results will not be accurate.
Not even blood tests, deemed the most reliable, are foolproof. Any incorrect handling of the sample could call into question the reliability of the results. Attorneys have also argued that BAC continues to rise after the traffic stop, meaning that someone below the legal limit at the scene might have a BAC over the legal limit once tested at the hospital.
After an arrest
Because drunk driving is such a serious offense, so, too, are the consequences. They can reach far beyond a fine or jailtime. They could affect the ability to get a job, obtain a commercial driver’s license, rent a property or more. Therefore, working with an attorney to challenge charges by calling into question the legitimacy of these tests can be wise.