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The most common chemical test used in Pennsylvania is the breathalyzer. The breathalyzer measures a DUI suspect's blood alcohol concentration (BAC) by taking a sample of the DUI suspect's breath. The breathalyzer uses infrared light to detect the amount of alcohol in the suspect's system. The Pennsylvania courts have sanctioned the breathalyzer as a scientifically reliable method of determining a suspect's BAC. There are two types of breathalyzers: "Type A" and "Type B." Most breathalyzers in use by Pennsylvania law enforcement officials are Type A breathalyzers. Type A breathalyzers give test results to police immediately and usually print out a reading. Conversely, Type B breathalyzer breath samples are sent away to a laboratory for analysis.

Various companies manufacture breath testing equipment. A particular model breathalyzer used by Pennsylvania law enforcement officials must be approved by the Pennsylvania Department of Health. The Department of Health periodically publishes a list of approved devices.

Section 1547(c)(1) of the Pennsylvania Motor Vehicle Code mandates that the Department of Health and Transportation prescribe rules and procedures regarding breath testing procedure. In order for the results of a breath test to be admissible, the prosecution must prove by a preponderance of the evidence that it comported with the following requirements* set forth by the Department of Health and Transportation:

Certification of Breath Test Operator

The breath test operator must be certified to operate the particular device he or she is using on the DUI suspect. The breath test operator must complete 30 hours of instruction on a particular model breathalyzer and be issued a certificate evidencing that he or she successfully completed the course. In order for a law enforcement official to qualify to use a different model breathalyzer the operator must complete another 8 hours of instruction on that particular model.

Accuracy Inspection Tests

For all "Type A" alcohol breath test equipment, an accuracy test shall be conducted every 30 days prior to using the breathalyzer in an actual breath test. An accuracy test consists of five simulator tests using simulator solution designed to give a reading of .10%. The device must not yield a result less than .09% or greater than .10%. If the device fails it must be placed out of service and repaired.

Annual Calibration of Type A Breathalyzers

A "Type A" breathalyzer must be calibrated annually within 1 year of using the equipment in an actual breath test. Calibration testing involves three separate series of five simulator tests using different numerical readings.

Observation Period

Before a breath test can be administered, there is a 20 minute observation period requirement. The breath test operator must observe the motorist for 20 consecutive minutes while the motorist has not ingested any alcoholic beverages, other fluids, regurgitated, vomited or smoked. The purpose of the observation period is to ensure accuracy of the breath test. Breath test results can be skewed by residual mouth alcohol or the use of other commercial products such as mouthwash.

Breath Test Procedure

The certified breath test operator shall conduct two consecutive breath tests on the motorist. Subsequently, the breath test operator shall give one simulator test using a simulator solution designed to give a BAC reading of .10%. The breath test operator must use in the prosecution the breath test with the lower BAC reading. The test results shall be disregarded and the breath testing device removed from service if the variation between the two actual breath tests given to the motorist is .02 or more or the simulator test result is less than .09% or greater than .10%.

*This list is not exhaustive and is merely a summary of the administrative regulations.