What is “blood alcohol content” (BAC) or level?

umber of drinks it takes for someone to reach this level depends on many factors, including type of alcohol, body weight, gender, and how quickly the person drinks. If you are arrested for a DUI, it’s important to understand how blood alcohol content is measured and how to craft a defense.

How BAC is Measured
There are two primary tests law enforcement use when a driver is suspected of being under the influence of alcohol: the breath test or breathalyzer and a blood test.

A breath test can be administered at the scene by measuring the amount of alcohol on the person’s breath and using it to estimate the percentage of alcohol in the person’s blood. Breath tests are noninvasive, but they do not actually measure alcohol in the blood. They are also the easiest to challenge. Breath test results may be challenged on the grounds that the machine was not calibrated properly, that the machine was not carefully maintained, or that the officer was not properly trained in its use, for example.

A blood test offers the most accurate measurement of someone’s blood alcohol content and the results of blood tests are usually favored by prosecutors and law enforcement. Blood tests are generally administered at a police station or lab when a trained professional draws blood from someone suspected of a DUI. The sample must then be analyzed by a qualified technician.

Factors That Impact BAC
BAC is merely the percentage of alcohol in the blood. The rate at which someone absorbs alcohol can be affected by many factors. This means that having three drinks over an hour can give one person a BAC of 0.07% but another person a BAC of 0.09%. Factors that influence how quickly someone becomes intoxicated or metabolizes alcohol include:

  • Weight
  • Body type (such as percentage of fat and muscle)
  • Gender
  • How fast the alcohol is consumed
  • Type and strength of the alcohol
  • Whether the drink was carbonated
  • Amount of food consumed and when
  • Some types of medication
  • Certain medical conditions

New York Law and Driving Under the Influence
Under New York law, there are two primary drunk driving charges: DWI (Driving While Intoxicated) and DWAI (Driving While Ability Impaired).

A DWI means the driver was legally intoxicated with a blood alcohol content at the legal limit of 0.08% or higher. A DWAI means the driver’s BAC was between 0.05% and 0.07% or there was evidence the driver was impaired. A DWAI is specific to the substance that caused the impairement such as DWAI-Alcohol or DWAI-Drugs.

A DWAI is usually less severe than a DWI. A first-time DWAI conviction can mean a fine of up to $1,000, up to 3 years of probation, up to 1 year in jail, and a minimum license suspension of six months. Penalties for a DWI conviction are similar but people convicted of a DWI conviction are required to install an ignition interlock device (IID) on their vehicle for one year. This device is basically a breathalyzer.

DWI can be charged if a driver is found to have a BAC of:

  • 0.08% or higher for a driver 21 years old or older
  • 0.04% for someone with a commercial driver’s license (CDL)
  • 0.02% for someone younger than 21 years old

If you have been arrested for DUI and a blood or breath test have shown a BAC of 0.08% or higher, it’s important to consult with an experienced New York defense attorney as soon as possible to begin building your defense.