In Iowa, impaired driving is called an OWI, or operating while intoxicated. Law enforcement may effectuate a traffic stop if they have probable cause or reasonable suspicion to stop a motor vehicle. Once stopped, if a law enforcement officer develops suspicion that a driver may likely be impaired, the officer may commence an OWI investigation.
Field sobriety tests
An officer may use standardized field sobriety tests. Three tests are most commonly used when detecting drunk driving based on National Highway Traffic Administration studies.
The horizontal gaze nystagmus test requires the driver to follow an object with their eyes held by the officer, such as a pen or finger. During this test, the officer looks for nystagmus, or uncontrolled jerking. During the walk-and-turn test, the officer checks for balance as the driver walks a straight, sometimes imaginary line. The one-leg stand test also checks for balance by requiring the driver to stand on one leg for 30 seconds.
Penalties for refusal
When drivers operate a motor vehicle, they have impliedly given consent for chemical testing. The officer must have reasonable grounds to believe a person is driving and under the influence, paired with at least one other factor to administer the test. Law enforcement must inform the driver of the driving revocation consequences of both failing the test or refusal. Drivers have the right to refuse field sobriety tests.
An OWI can have many legal consequences for the driver. Field sobriety test are not scientific. If the driver feels that mistakes were made, an experienced criminal defense attorney can help.