Legal Definitions - driving while ability-impaired

Driving While Ability-Impaired (DWAI) refers to the legal offense of operating a motor vehicle when a person's physical or mental faculties are diminished to an extent that makes driving less safe, but not necessarily to the severe degree associated with a "driving under the influence" (DUI) charge. In jurisdictions that recognize DWAI as a distinct offense, it often involves a lower threshold for impairment, such as a lower blood alcohol content (BAC) level than what is required for a DUI conviction, or impairment by substances other than alcohol. The core concept is that the driver's ability to operate the vehicle safely is compromised.

• Example 1: Alcohol Impairment Below DUI Threshold

  A driver is stopped for a broken taillight. During the interaction, the officer notices a faint smell of alcohol. A breathalyzer test reveals the driver's blood alcohol content (BAC) is 0.06%. In a state where the legal limit for a Driving Under the Influence (DUI) charge is 0.08% BAC, but a DWAI offense can be charged at 0.05% BAC or higher, this driver could be charged with DWAI. Even though their BAC is below the DUI threshold, their ability to drive safely is legally considered impaired.

• Example 2: Impairment by Prescription Medication

  A person takes a new prescription painkiller that causes significant drowsiness and blurred vision, effects clearly warned about on the medication label. Despite these warnings, they decide to drive to an appointment. While driving, they swerve slightly and miss a turn due to their impaired vision and slowed reaction time. If pulled over by law enforcement and found to be under the influence of the medication to a degree that compromises their driving ability, they could face a DWAI charge, as their capacity to operate the vehicle safely is diminished by the drug.

• Example 3: Impairment by Cannabis

  An individual consumes cannabis and, a few hours later, decides to drive home. Although they believe they are functioning normally, the psychoactive effects of the cannabis have subtly slowed their reflexes and altered their perception of speed and distance. If stopped by law enforcement and, through field sobriety tests or other evidence, found to be under the influence of cannabis to a degree that impairs their driving ability, they could face a DWAI charge. Their ability to drive safely is compromised by the substance, even if they do not appear overtly intoxicated.