Blood Alcohol Limit (BAC) in Texas: Everything You Need to Know

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In the state of Texas, anyone who operates a motor vehicle in a public place while intoxicated commits the offense of driving while intoxicated (DWI), known in some other states as driving under the influence or DUI. While intoxication can include consuming sufficient alcohol or drugs to impair a driver's normal faculties, Texas, like most states, also legislates a legal limit. This is not measured by how many alcoholic beverages a driver consumes, but by the percentage of alcohol concentration in a driver's blood or breath.

Driving While Intoxicated in Texas

It is an offense to drive a motor vehicle in Texas while intoxicated. In most cases, this is a criminal offense, punishable by imprisonment, fines and loss of driving privileges, among other sanctions. The level of punishment under Texas law depends in part on the driver's prior criminal record and also on the circumstances of the DWI.

Like in most states, Texas law sets out two different methods of establishing that a driver was operating a motor vehicle while under the influence. The first is based on observable evidence of impairment. If the prosecutor can convince a jury that the driver's normal faculties were impaired by alcohol or drugs, the driver is convicted of a DWI.

The second method of defining intoxication is by determining the blood alcohol content (also called blood alcohol concentration) of the driver. This measurement is referred to as the BAC. If a driver's BAC is over the legal limit, they are presumed guilty of a per se DWI.

Testing Blood Alcohol Concentration

A driver's BAC is the measurement of the percentage of alcohol that is found in their blood. This is determined by a chemical test of the breath, blood or urine of the driver. Drivers are deemed to have consented to these tests in Texas, and additional sanctions apply if they refuse to take them.

The breathalyzer test is the most common test used by police officers in DWI cases in Texas. This is a breath test where an individual is directed to blow into a breathalyzer device. The blood test is more invasive and usually performed in a clinical setting. The urine test is said to be less accurate and is used less frequently.

This chemical testing offers an objective way to determine the percentage of alcohol present in an individual's body. The higher the BAC level, the greater the person's intoxication level.

What Is the Legal BAC Limit in Texas?

Texas law defines intoxication as having a BAC of 0.08 percent or greater. That means that any driver found to have a BAC of 0.08 percent or greater while operating a motor vehicle in public in Texas is presumed to be intoxicated. The driver is permitted to offer evidence that they were not intoxicated, but in order to avoid conviction, this evidence must be strong enough to overcome the legal presumption.

This legal BAC limit applies to those driving with a regular driver's license. Those driving with a commercial license in Texas are subject to a much lower limit, a BAC that is half of the regular legal BAC limit. If a commercial driver has a BAC of 0.04 percent or above, they are presumed intoxicated and can be convicted of a DWI under state law.

Understanding the BAC

It might seem easier to avoid a DWI if the legal limit were based on the number of drinks a person consumed. But while there is a relationship between drinks consumed and BAC, it is anything but direct. This much is true: The more alcohol a person drinks, the higher their BAC will be. But trying to figure out exactly how much a particular person can drink before hitting the 0.08 percent limit isn't easy.

A person's BAC registers the percentage of alcohol in their blood. The amount of alcohol that passes into their bloodstream depends on several factors, including the number of drinks consumed as well as the amount of alcohol in each drink. For example, a light beer will have less alcohol than a shot of vodka. In addition, the person's gender, weight, recent food consumption, water intake and age, among other factors, all enter into the percentage of alcohol in a driver's system.

Effects of Alcoholic Beverages

A chart attributed to the National Highway Safety Association estimates the effects of alcoholic drinks on a male adult. Drinks are described as one serving of 1.5 ounces of 80 proof liquor, a 12-ounce beer of 4.5 percent alcohol or a 5-ounce glass of wine that is 12 percent alcohol.

Two drinks are generally sufficient to render a person intoxicated if they weigh 100 pounds, three drinks will render a man up to 140 pounds intoxicated, while five drinks will render a man of any weight intoxicated.

It takes less alcohol for a woman to have a BAC of 0.08 percent. Obviously, the amount of time in which the alcohol is consumed also plays a role in the BAC. The chart states that food consumption will also affect the BAC.

Penalties for Texas DWIs

The penalties for a per se DWI, based on BAC, are the same as for a DWI based on evidence of impairment. But that does not mean that every driver convicted of a DWI gets the same penalties. As is true with most criminal convictions, penalties depend on the prior record of the accused.

A driver who has never had a prior conviction for operating a vehicle under the influence is subject to lighter sanctions than those with multiple prior DWIs. And with each additional prior offense, the penalties increase.

It is important to note that other offenses involving intoxication can count as priors for a DWI charge in Texas. A conviction of any of these offenses will count as a prior for any other:

  • operating a motor vehicle while intoxicated
  • operating an aircraft while intoxicated
  • operating a watercraft while intoxicated
  • operating or assembling an amusement ride while intoxicated

Other Potential Penalties Under Texas DWI Laws

For a first offense of DWI in Texas, a driver is charged with a Class B misdemeanor. The driver is subject to a fine of up to $2,000, can be imprisoned for up to 180 days and faces a driver's license suspension of 90 days to one year. If they wish to retain their license during the suspension, drivers will face an annual fee every year for three years.

A second offense in Texas is also charged as a Class B misdemeanor. The fine can be up to $4,000, and the driver will be sentenced for a term of between 30 days and one year of jail time. Their license will be suspended for at least one year with the same annual fee for three years as for a first offense.

A third offense is a third-degree felony in Texas. That means that the period of imprisonment can exceed one year. The driver can be fined up to $10,000 and will be sentenced to a term in prison of between two and 10 years. Their license will be suspended for a period of between one and two years, and they will face the same annual fee to retain their license as for a first offense.

Other Possible Drunk Driving Penalties

Other penalties are possible and likely, including probation with a mandatory period of community service, mandatory attendance at a DWI education program and the mandatory installation of an ignition interlock device (IID) in every vehicle they own or use regularly. The IID is a type of breathalyzer that will not allow the vehicle to start if the machine detects alcohol use.

A BAC higher than 0.15 percent and having a passenger in the vehicle under the age of 15 are both aggravating circumstances that will result in higher penalties. And if another person is injured or killed as a result of the DWI, the charge is much more serious.