Preliminary Alcohol Screening Test

Types of Tests:

During a Preliminary Alcohol Screening (PAS) test, an officer at the scene of the incident uses an alcohol breath test kit or breathalyzer. Although taken voluntarily by the suspected drunk driver, refusal to take the test generally results in immediate license revocation until further chemical tests can be performed.

The PAS tests are often considered part of an officer’s field sobriety tests. They are used as a means of early intoxication detection before more reliable tests, such as urine or blood sampling, are possible.

Although most courts reject the results of PAS or breathalyzer tests as evidence for a conviction, the PAS provides officers with an advantageous tool. The convenience of a PAS device can help an officer detect possible drunk drivers as well as drivers under the age of 21 who have been drinking illegally.

If an officer who has administered a PAS test discovers an underage (under 21) driver to have a BAC percentage of .01 % or greater, the officer can suspend his or her driver’s license. Most states have zero tolerance laws that carry very steep penalties for drivers under 21 who are driving with any alcohol in their system.

Unfortunately, the accuracy of PAS devices or portable breathalyzers is questionable. In fact, research indicates that PAS testing device results vary an average of at least 15% from actual BAC percentages. That means approximately one in four of all individuals tested will have a BAC reading that is higher than their actual BAC.

The device is designed to indirectly measure the amount of alcohol in a driver’s body. Using fuel cell technology to create an electric current, the PAS device then generates a numerical value for the current. This number is the BAC percentage.

Due to the test’s overall inaccuracy, officers generally request that a Preliminary Alcohol Screening test taken on the road be followed by a stationary breathing test, or urine or blood test at the station upon arrest. The on-scene device should only be used as proof of reasonable suspicion of driver intoxication.