25: Measuring Intoxication

The common measures of intoxication are blood alcohol content, BAC, and visible intoxication.

• BAC is determined by chemical analysis of the blood, breath or urine. BAC is the legal standard police and courts use to determine levels of intoxication.
• Visible intoxication is the standard servers must use in determining intoxication. That is, something that can be observed.

Explanation of BAC

BAC, or blood alcohol content, is the amount of alcohol in the bloodstream that is measured in percentages. For example, a 0.10 percent BAC is 1 part alcohol per 1,000 parts of blood. We just learned how the absorption rate factors impact how quickly alcohol is absorbed into the bloodstream once consumed, directly affecting a person’s BAC.

Although servers can’t know a customer’s BAC, it is important to understand that BAC rises when a person consumes more alcohol than the liver can metabolize. When alcohol consumption stops, BAC decreases as time elapses. Remember, an average healthy person will eliminate approximately one standard drink per hour. Therefore, time is the key factor in eliminating alcohol.

BAC and visible impairment are not always directly related. Customers with high tolerance, the body’s ability to hide the visible signs of intoxication, can drink large amounts of alcohol and not show signs of visible intoxication, yet still be considered legally intoxicated because of their BAC level.

BAC is the legal standard police and courts use to determine levels of intoxication. Intoxication is based on the amount of alcohol in a person’s blood. In Pennsylvania, it is illegal to operate a motor vehicle with a BAC of 0.08 percent or higher.

Note: A CDL driver can be charged with a DUI if the alcohol concentration in the individual’s blood or breath is:

(i)0.04% or greater within two hours after the individual has driven, operated or been in actual physical control of the movement of a commerical vehicle other than a school bus or school vehicle.

(ii) 0.02% or greater within two hours after the individual has driven, operated or been in actual physical control of the movement of a school bus or a school vehicle.

Slide 25: Measuring Intoxication