For a Massachusetts police officer to arrest you for drunk driving, they need probable cause. In fact, they need either your consent or probable cause to demand a chemical breath test.
The questions police officers ask during a traffic stop can help them establish probable cause, but they often depend on a field sobriety test to justify a request for chemical testing. If you fail any of the three field sobriety tests below, that could directly lead to an officer demanding a chemical breath test.
The walk-and-turn test
People often have issues with balance and spatial perception while under the influence of alcohol. Officers can test someone for impairment by asking a driver to walk in a straight line, turn 180 degrees and walk back in the same straight line. Individuals who lose their balance or who cannot walk in a straight line will have failed the test.
The one-leg stand
Maintaining your balance is significantly more difficult when you have to stand on one leg. The one-leg stand test requires that you do exactly what the name implies, often while counting backward or performing another simple mental task.
The horizontal gaze nystagmus test
Perhaps the hardest to manipulate of all the field sobriety tests, the horizontal gaze nystagmus test looks for signs of a natural muscle spasm. The spasm becomes more visible and stronger when people consume alcohol.
If a driver doesn’t perform the way an officer expects on any of these field sobriety tests, that may be the probable cause the officer needs to request a breath test. Understanding the rules that apply to impaired driving charges can help you plan to defend yourself.