If police stop a driver under suspicion of drunk driving, chances are the officer will ask the driver to step out of the car and submit to a Standardized Field Sobriety Test battery. Field sobriety tests consist of three activities to measure the driver's balance, reflexes and coordination to confirm whether the driver is impaired by alcohol. These tests are by no means scientific and often have entirely subjective results. Understanding how they work and the driver's right to refuse may prevent Colorado drivers from unwittingly surrendering their rights.
There are three parts to a field sobriety test. The walk and turn requires the subject to walk heel to toe in one direction before turning and walking back in the same manner. The horizontal gaze nystagmus tests allows the officer to watch the reflexes of the subject's eyes as he or she follows the officer's finger. The one-leg stand requires the driver to stand on one leg while counting as the officer directs. For this test alone, studies show that nearly half of sober subjects would fail even under ideal conditions.