Final answer:
An underage driver may be required to take a second alcohol screening test if the first test reveals a BAC of 0.02% or higher, due to stricter underage drinking laws.
Step-by-step explanation:
When an underage driver undergoes a preliminary alcohol screening and the test reveals a Blood Alcohol Concentration (BAC) of 0.02% or higher, the officer may require the driver to take a second test.
This threshold is notably lower than the 0.08% BAC limit that is the standard for legal intoxication for drivers aged 21 and over, reflecting stricter laws that apply to underage drivers. It is critical to note that metabolism rates of alcohol differ for individuals, but on average, the human body breaks down alcohol at a rate of about 0.015% BAC per hour.
The Breathalyzer is a commonly used device for estimating a person's BAC based on the ethanol content in their breath. The reaction used in a Breathalyzer involves the oxidation of ethanol, leading to a color change in the testing solution, allowing the officer to measure intoxication levels.