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Blood Alcohol Limits: The Basics

Blood Alcohol Limits: The Basics

Blood Alcohol Limits: The Basics Blood alcohol limits are the legal standards by which a driver can be charged with driving under the influence, DUI, or driving while intoxicated, DWI. The United States have adopted 0.08 percent blood alcohol content as the legal measurement of impairment.

Blood Alcohol Content

Blood alcohol content, referred to as BAC, is the chemical measurement of the percentage of alcohol in the blood. A BAC of 0.25 means that 25 percent of the total blood volume contains alcohol. A driver's BAC is determined through chemical testing, such as a blood test, urinalysis or breathalyzer. BAC varies according to gender, weight and amount of alcohol consumed during one hour. It is estimated that a 120-pound woman who consumes three alcoholic beverages in one hour can have a BAC of .13 percent, which is over the legal limit. Conversely, a 180-pound man who consumes the same amount of alcohol can have a BAC of .07 percent.

Penalties For Driving Under The Influence Of Alcohol

The U.S. has imposed strict drunk driving laws as a means to prevent DUI offenses. Severe penalties can be imposed, including license suspension or revocation, fines, jail time, probation or mandatory participation in an alcohol diversion program. Some states require the installation of an ignition interlock device, which automatically measures a driver's breath for evidence of alcohol. If alcohol is detected, the ignition is disabled, preventing the driver from operating the vehicle.

What Happens During A Traffic Stop And What Are My Rights?

If you are stopped by law enforcement officers for suspicion of DUI, you may be asked to perform field sobriety testing or consent to a breathalyzer test. Breathalyzers are commonly used during traffic stops to determine whether a driver has exceeded blood alcohol limits. Field sobriety tests are designed to detect impaired muscle coordination and impaired visual perception.

If you are suspected of a DUI, you have legal rights. You are required to provide your driver's license and vehicle registration to law enforcement officers, but you are not required to participate in field sobriety testing. You are not required to exit your vehicle. You should advise the officer that you exercise your Fifth Amendment rights to remain silent. Do not answer questions concerning your alcohol consumption. Under the laws of implied consent, you must submit to breathalyzer testing. Refusal can result in the immediate suspension or revocation of your driving privileges. If you are arrested and charged, you should immediately contact a DUI attorney to assist in your defense.