What Is BAC and How Is It Involved in DWI Cases in New Jersey?

New Jersey’s driving while intoxicated (DWI) statute gives prosecutors two methods of establishing that a defendant was too impaired to operate a vehicle legally. They can introduce evidence indicating that the defendant’s behavior and appearance at or near the time they were driving were consistent with intoxication due to alcohol or drugs. Prosecutors may also prove intoxication by showing that a defendant’s blood alcohol content (BAC) was above a certain level. What is BAC, though? Simply put, it is a measurement of how much alcohol is present in a person’s body. How police measure BAC is often a matter of controversy, so a New Jersey DWI attorney’s knowledge of how state law uses BAC is important to understanding how to defend against DWI charges.

BAC in New Jersey DWI Law

The DWI statute defines the offense as either:
1. Driving “while under the influence of” drugs or alcohol; or
2. Driving with BAC of at least 0.08 percent.
With evidence that a defendant had BAC of 0.08 percent or more, the state does not necessarily have to provide evidence of extrinsic details like bloodshot eyes or the odor of alcohol. New Jersey law presumes that a person was intoxicated, and therefore unable to drive, when their BAC was above the “legal limit.” This is often known as per se DWI.

State law requires every driver to submit to breath testing to determine BAC, and makes refusal a separate motor vehicle offense. A defendant can challenge the admissibility of the state’s BAC evidence based on a 2008 decision by the New Jersey Supreme Court, which established procedures that police must follow to calibrate and maintain the Alcotest devices used to perform breath tests.

What Does BAC Measure?

BAC describes the mass of alcohol in a specific volume of blood. If someone has BAC of 0.08 percent, there are 0.08 grams of alcohol for every 100 milliliters of blood. Devices like the Alcotest measure the amount of alcohol in a person’s breath, and then extrapolate the amount of alcohol present in their blood.

The more alcohol that is present in a person’s blood, the more impaired they are likely to be. BAC of 0.08 percent is the “legal limit” for DWI in New Jersey and throughout the U.S. The legal limit is lower for certain people, such as commercial truck drivers, school bus drivers, and drivers under the age of 21.

Why 0.08 Percent?

The use of 0.08 percent BAC as a nationwide standard is largely the result of federal legislation that directs — and withholds — highway funding. In 1998, Congress created a grant program to encourage states to enact per se DWI laws with a 0.08 percent limit. This number was based on recommendations from both federal agencies and private organizations.

Two years later, Congress passed a law that withheld highway funds from states that did not enact 0.08 percent laws by 2004. Congress did something similar with the National Minimum Drinking Age Act of 1984, which withheld highway funds from states that did not prohibit people under the age of 21 from purchasing alcoholic beverages.

DWI attorney Evan Levow advocates for the rights of people in New Jersey who have been charged with alleged DWI in New Jersey courts. He can advise you of your rights and options, guide you through the municipal court system, and prepare the best possible defense for your case. To schedule a free and confidential consultation to see how we can help you, please contact us today online or at (877) 593-1717.

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