New Jersey prosecutors can prove guilt in driving while intoxicated (DWI) cases by presenting evidence showing beyond a reasonable doubt that a person was impaired by alcohol or drugs while operating a vehicle. They can also prove guilt, at least with regard to impairment by alcohol, by showing that a person’s blood alcohol content (BAC) was at least 0.08 percent. Police can measure BAC using samples of a person’s breath or blood. For drugs other than alcohol, they must test blood or urine. Drug testing is far from a settled science, and false positives still occur quite often. DWI defense in New Jersey requires careful examination of evidence that supposedly shows positive drug test results or BAC above the “legal limit” of 0.08 percent.
State law requires drivers to submit breath samples for BAC testing. Anyone driving on New Jersey’s public roads is considered to have consented to breath testing. Refusal to submit breath samples is a motor vehicle offense that could be charged along with DWI. Blood and urine samples still require either a search warrant or a driver’s consent.
Police in New Jersey use a device known as the Alcotest to test breath samples for BAC. Unlike blood or urine samples, breath samples cannot be stored for later testing. The Alcotest is therefore designed to perform tests at police stations, not laboratories. A person blows into a tube, and the device subjects the breath sample to chemical reactions. The device requires frequent maintenance and careful calibration.
False positives can occur with the Alcotest because of improper maintenance, or because of a variety of contaminants that may be present in or around a person’s mouth. I was involved in the 2008 landmark decision by the New Jersey Supreme Court that established procedures for the maintenance and operation of Alcotest devices. For example, police must observe a DWI suspect for twenty minutes before administering the breath test, to ensure that they do not regurgitate or place anything in their mouth.
It may still be possible, however, for a device to return a false positive. This could occur because of something that was already present in the mouth, such as traces of alcohol. Exposure to certain types of chemicals could even make it more likely for a person’s breath to appear to contain alcohol.
Police officers with special training can administer breath tests in New Jersey, and almost any police officer can direct a DWI suspect to provide a urine sample. Collecting a blood sample, however, requires a trained medical professional. Errors during a blood draw can result in contamination of a sample, which could lead to a false positive result for alcohol or drugs. Improper handling of a blood or urine sample could also result in contamination and a false positive.
Certain legal substances can produce false positive results. Medications used to treat ADHD, for example, could show up in a drug test as amphetamine.
If you have been charged with alleged DWI in a municipal court in New Jersey, you need an experienced advocate who can help you understand options and fight for your rights. DWI lawyer Evan Levow is available to assist you. Please contact us online or at (877) 593-1717 today to schedule a free and confidential consultation.