Chemical Testing Breath, Blood & Urine in New Jersey DWI Cases

In order to prove guilt in driving while intoxicated (DWI) cases in New Jersey, law enforcement must show that a defendant was under the influence of either alcohol or certain types of drugs. State law allows them to use chemical tests that allegedly show the presence of alcohol or drugs. Chemical testing for alcohol has an extensive body of law addressing how police must collect and test samples of a DWI suspect’s breath. For other drugs, they must use samples of blood or urine. This type of testing can be much less certain, both scientifically and legally. Urine testing, in particular, has significant reliability issues. If the state tries to introduce results from urine tests, DWI attorneys must carefully examine the evidence to look for errors.

New Jersey has used chemical testing in DWI and DUID cases for decades. In 1964, the New Jersey Supreme Court held that “[a]lcoholic content in the blood furnishes a scientific measure of the extent of the influence of liquor upon the person.” It went on to state that “chemical analysis of the blood itself, urine, breath and other bodily substances is a scientifically accurate method of ascertaining that content.”

State law currently defines the offense of DWI in two ways: “operat[ing] a motor vehicle” either (1) while impaired by an “intoxicating liquor, narcotic, hallucinogenic or habit-producing drug;” or (2) “with a blood alcohol concentration [BAC] of 0.08% or more by weight of alcohol in the defendant’s blood.” BAC above the “legal limit” of 0.08% creates a presumption that the defendant is legally impaired by alcohol. The state’s implied consent statute makes breath testing mandatory in DWI investigations.

New Jersey law does not set a specific “legal limit” for the presumption of impairment by drugs besides alcohol. It also has no implied consent law for blood or urine samples. Both require consent or a warrant.

In cases involving driving under the influence of drugs (DUID), prosecutors must rely on blood or urine test results, or on testimony from police officers with certification as drug recognition evaluators (DREs). DREs use a 12 step process to often guess a specific type of drug. This lack of specificity makes chemical testing quite important to prosecutors, but it has its own reliability problems.

Nearly every police station in New Jersey has an Alcotest device to test breath samples for BAC. To test a urine or blood sample, police must send the sample to a lab. They must document every step of the chain of custody, starting with the DUID suspect and ending with the lab technician who completes the testing process. Errors may occur at every step along the way, and those errors could compromise the reliability of the test results.

Testing urine and blood samples also has inherent reliability problems. False positives are fairly common, meaning that a legal and safe drug, such as a prescription medication, ends up looking like something illegal or dangerous. Every drug breaks down in the body at a different rate, so the urine and blood testing that New Jersey State Labs perform cannot determine when a person took a particular drug. Urine and blood esting in New Jersey is qualitative, not quantitative. It can show the present of a substance, but it does not show the amount of the drug in the sample. A positive test for cannabis, for example, cannot say for certain whether the individual consumed cannabis a few hours or a few days before police pulled them over.

DWI lawyer Evan Levow advocates for the rights of people who are facing alleged DWI charges in New Jersey municipal courts. He can advise you of your rights and options, and prepare the best defense possible for your case. To schedule a free and confidential consultation with a member of our team, please contact us today online or at (877) 593-1717.

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