A preliminary breath test (PBT), sometimes referred to as an “alcohol screening devise,” is a roadside breath test. This should be distinguished from the breathalyzer device used by police at the police station. The results from the test at the police station will ultimately be used against a defendant in court. The PBT, on the other hand, is used only to determine if there is probable cause to arrest a suspected drunk driver.
In fact, by statute, the results of a PBT are not admissible against a defendant in court. The reason these tests are not admissible is that they are notoriously unreliable. However, the results of these tests are admissible to establish that the officer had probable cause to arrest the defendant and request that the defendant perform a chemical test. Thus, PBT’s are highly relevant at DMV hearings and in motions to suppress results of any chemical test that is administered by the police.
Generally, there are two types of PBT devices in use by police: fuel cell devices and gas sensor devices. Neither type of device is very accurate. For example, the fuel cell devices will detect a large number of compounds in addition to alcohol which may trigger a false positive. In addition, the results may be contaminated by mouth alcohol (alcohol that exists naturally in the mouth). Moreover, the suspect must be observed continuously for 15-20 minutes before administering the test in order to ensure that the suspect’s breath is not contaminated by belching, burping, or regurgitation. However, police rarely follow this procedure when administering a PBT. In addition, the gas sensor devices are prone to error as well. For instance, a gas sensor may detect alcohol from sources other than the suspect’s breath, such as an open alcohol container or spilled drink.
Despite the inherent problems with PBT devices, an adverse result can be highly persuasive to a judge or hearing officer at the DMV. However, a skilled DUI attorney can effectively cross-examine the officer and determine if the PBT was administered correctly. In addition, if the device used was not approved by the executive director of the department of public health and environment, then the test cannot be considered.
