Since the 1950s, scientists have worked to improve the methods of detecting and measuring the amount of alcohol in the blood of someone authorities suspect of drinking and driving. Using a chemical method of oxidizing alcohol on a driver’s breath, modern devices are supposedly more accurate than those early “drunkometers.” In fact, many law enforcement officers use portable breath tests at traffic stops to obtain preliminary blood alcohol concentration results.
However, the accuracy of a PBT is questionable enough that many contend they should not be law enforcement tools but merely for personal use. While the blood alcohol tests officers perform at the police station may be more sophisticated, too many factors can affect the accuracy of a portable test, making it unwise to submit to a PBT if police pull you over.
What affects the accuracy of the PBT?
In Minnesota and most states, it is a separate violation to refuse to submit to alcohol testing. Such refusals can result in jail time, thousands of dollars in fines and the revocation of your driver’s license even if the court never convicts you of driving while impaired. Nevertheless, even a single point on your BAC can determine whether police arrest you. Because of the design of the portable testers, any of the following factors may throw the test results off:
- Substances in your mouth that contain alcohol, such as cough medicine or mouthwash
- Certain conditions in your respiratory system
- Other physical conditions, including cancer, liver disease or diabetes
- Substances within close proximity of the test, such as fumes from paint thinner
- Certain foods you have recently eaten
The device itself may be problematic, particularly if it has defective software, is improperly calibrated or if the administrating officer is not trained to use the device correctly. An officer may be unfamiliar with the manufacturer’s recommendations for using the device, or the officer may neglect to obtain multiple readings for accuracy.
If you decide to refuse to submit to a portable breath test, you can expect officers to arrest you and take you to the police station for additional testing. Implied consent laws state that your cooperation with BAC testing after your arrest is mandatory, but you may have strong feelings about providing self-incriminating evidence. However, you have the right to consult with an attorney before you submit to any alcohol testing, whether at the side of the road or in a police station.