When can law enforcement administer field sobriety tests?

Law enforcement officers are authorized to administer field sobriety tests when they observe signs of impairment or have probable cause to believe that a driver is under the influence of alcohol or drugs. This is based on the principle that probable cause must be established before any field sobriety testing occurs. Signs of impairment can include erratic driving behavior, bloodshot eyes, slurred speech, and an odor of alcohol. These indicators provide the officer with the necessary basis to conduct further testing to assess the driver’s level of intoxication.

Field sobriety tests are designed to objectively measure a person's physical and cognitive abilities that can be affected by alcohol or drugs. If an officer does not have a valid reason, such as observable indicators or probable cause, the administration of such tests may not be permissible and could undermine the legal process.

Additionally, the other options do not align with established protocols: a warrant is not typically required for field sobriety tests; a voluntary request from a driver for a test doesn't grant law enforcement the authority to administer it if they lack probable cause; and conducting tests during a roadblock without any prior observation of impairment misses the critical component of establishing reasonable suspicion or probable cause.