Jun 25

What is an Approved Screening Device?

An approved screening device refers to a breathalyzer or similar instrument that measures the alcohol concentration in a person’s breath. These devices are typically approved by regulatory bodies responsible for enforcing laws related to impaired driving. The result of the ASD is used to build ground to arrest a driver who is believed to be impaired by alcohol.

What is Blood Alcohol Concentration?

Blood Alcohol Concentration (BAC) refers to the amount of alcohol present in a person’s bloodstream. It is a measure of the alcohol content in the body and is commonly used to determine a person’s level of intoxication or impairment due to alcohol consumption.

BAC is typically expressed as a percentage, representing the ratio of alcohol to blood volume. For example, a BAC of 0.08% means that 0.08% of a person’s blood, by volume, is alcohol.

The effects of alcohol on the body can vary depending on an individual’s BAC. As BAC increases, alcohol can affect coordination, reaction time, judgment, and overall cognitive functioning. Higher BAC levels are associated with greater impairment, making it more dangerous to perform tasks such as driving a vehicle.

BAC can be influenced by various factors, including the number of standard drinks consumed, the rate of consumption, body weight, metabolism, and individual tolerance to alcohol.

What is a Standard Field Sobriety Test (SFST)?

A Standard Field Sobriety Test (SFST) is a series of standardized physical and cognitive tests administered by law enforcement officers to determine whether a person is impaired by alcohol or drugs while operating a vehicle. SFSTs are commonly used during traffic stops and DUI investigations.

The three main tests are:

  • Horizontal Gaze Nystagmus (HGN): The officer observes the person’s eyes as they follow a moving object, typically a pen or small flashlight. Nystagmus refers to an involuntary jerking of the eyes that becomes more pronounced when a person is impaired. The officer checks for specific eye movement patterns associated with alcohol or drug impairment.
  • Walk and Turn (WAT): The person is instructed to take nine heel-to-toe steps along a straight line, turn, and return in the same manner. The officer looks for indicators such as balance issues, inability to follow instructions, improper turning, or stepping off the line. These may suggest impairment.
  • One-Leg Stand (OLS): The person is asked to stand on one leg while keeping the other foot raised around six inches off the ground. They must count aloud by thousands (one thousand-one, one thousand-two, etc.) until instructed to stop. The officer looks for signs of swaying, hopping, using arms for balance, or an inability to maintain the position, which can indicate impairment.

What is a Breathalyzer?

A breathalyzer is a portable device used to estimate a person’s blood alcohol concentration (BAC) by analyzing their breath. It is commonly employed by law enforcement agencies to assess whether an individual is driving under the influence of alcohol or to determine if they have consumed alcohol in violation of legal restrictions (i.e. over 80).

The term “breathalyzer” is often used generically to refer to any breath alcohol testing instrument, regardless of the specific brand or model. These devices operate on the principle of alcohol being present in the breath in proportion to its concentration in the bloodstream. When a person exhales into a breathalyzer, the device measures the alcohol content in their breath and converts it into a BAC reading.