Breath test laws in the United States are designed to enforce drunk driving regulations by measuring blood alcohol concentration (BAC). If you're pulled over under suspicion of driving under the influence (DUI/DWI), law enforcement may administer a breath test using a breathalyzer device. Refusing to take a breath test can lead to immediate penalties like license suspension due to "implied consent" laws, which state that by driving, you've implicitly agreed to BAC testing if suspected of DUI. The legal BAC limit for drivers is typically 0.08%, but some states have lower limits for certain drivers or additional penalties for higher BAC levels. Breath test results can be challenged in court for inaccuracies due to device malfunctions, improper calibration, or individual physiological factors, making legal counsel crucial if you're facing charges based on breath test results.