People who drink and drive worry about the number of drinks they may consume and still be considered under the legal limit for driving while intoxicated (DWI) or driving under the influence (DUI). There are various factors that can affect a person’s level of intoxication, such as the following:
- A person’s weight;
- The type of drinks they consume and the alcohol content of the drinks;
- Whether they consume food at the same time they ingest alcohol;
- The time within which a quantity of alcohol is consumed.
There are additional factors as well, such as how rested and fit or fatigued a person is when they start drinking beverages containing alcohol, that determine the resulting level of intoxication. There are some general guidelines that can help a person gauge the number of drinks they might consume before they risk becoming too intoxicated to drive.
Blood alcohol content (BAC) is also referred to as “blood alcohol concentration” or “blood alcohol level”. All of these terms refer to a measurement of alcohol intoxication that is used for legal or medical purposes. For example, a BAC of 0.10%, or one tenth of one percent, means that there is 0.10 g of alcohol for every 100 ml of blood in a person’s body. A BAC of 0.0, or no alcohol in the body, means that a person is sober.
But the most important BAC figure in the U.S. is 0.08, because a BAC of 0.08 or above is the level that is considered intoxication for purposes of the criminal law in all states. If a person with a BAC of 0.08 or higher drives a motor vehicle in any state in the U.S., they can be charged with drunk driving.
In some states, the BAC limit can be even lower for certain people, such as commercial drivers and drivers under 21 years of age. But anyone whose BAC is above 0.08 is very impaired. A BAC level that is higher than 0.40 is potentially fatal.
What Is Blood Alcohol Concentration?
Blood alcohol concentration is the amount of alcohol in a person’s body in relation to the amount of blood in their system. For example, a BAC level of 0.08, which is, again, the legal limit, means that the amount of ethanol in a person’s system may not exceed .08 grams in 100 milliliters of blood, or .08 grams in 210 liters of breath.
The chart below helps a person understand how many alcoholic beverages lead to a certain BAC depending on a person’s weight in pounds.
Drinks Weight in Pounds
Blood Alcohol Content
Approximate Blood Alcohol Percentage
One drink is 1 liquid, or fluid, ounce of 100 proof alcohol, 12 liquid ounces of beer, or 4 liquid ounces of wine. One fluid ounce is equal to about 2 tablespoons of liquid or one-eighth of a cup of fluid. It can be helpful for a person to measure out these amounts in their home kitchen. They may then appreciate what a small quantity of a beverage can be intoxicating.
So, 8 liquid ounces of wine can be enough to lead to intoxication of a person who weighs 100 pounds. If 4 liquid ounces equal about one-eighth of a cup, then 8 ounces equals about one-fourth of a cup. That is very little wine.
In California, a person can be charged with driving under the influence, if they have a BAC of 0.08 or more whether or not they are actually intoxicated and whether or not their driving ability is actually affected. A person’s BAC is measured by either a breath test or a blood test.
The penalty for a first driving under the influence (DUI) conviction in California is:
- Summary Probation: 3 to 5 years of summary probation;
- Attendance at DUI school: This is as follows:
- If a person’s BAC is lower than 0.20%, they must attend DUI school for 3 months, or about 30 hours;
- If a person’s BAC is 0.20% or higher, they must attend DUI school for 9 months, or about 90 hours;
- Victim Impact Panel (VIP) Attendance: A VIP is a program put on by Mothers Against Drunk Driving (MADD) to foster awareness of the impact of driving under the influence. Whether or not a person is required to participate in a VIP after a DUI may depend on the types of charges, the county, and even the specific judge. Most referrals to the VIPl are part of the DUI classes that may be ordered by the court as a condition of probation;
- Fines: Fines of $390 to $1,000 can be charged, plus a penalty assessment. Note that this means that a minimum fine of $390 is imposed;
- A 6-month Driver’s License Suspension: A person’s driver’s license can be suspended for 6 months, but a person may be able to resume driving right away if they install an ignition interlock device (IID) in their cars for 6 months. An IID is a miniature DUI breath test instrument that is installed in the dashboard of a person’s car. It prevents a person from operating their car unless they provide an alcohol-free breath sample;
- 48 Hours to 6 Months in Jail: A person can be sentenced to jail time, but a court can grant probation, in which case they would probably not have to serve time in jail, and
work release is possible depending on the county in which a person is convicted.
In Texas, a first DUI offense is a Class B misdemeanor. The penalties are as follows:
- A jail term of from 72 hours to 180 days;
- A fine of up to $2000;
- Driver’s license suspension of 90 days to 1 year.
A second offense can lead to from 30 days to 1 year in jail and a fine of up to $4000. In addition, a person’s driver’s license may be suspended or revoked for a period of from 180 days to 2 years.
In New York, a person commits a DWI offense by driving a vehicle:
- While in an intoxicated condition, (DWI);
- Within a BAC of .08% or more (DWI per se).
So a person who operates a vehicle with a BAC of .08% or more commits DWI per se. This means that guilt does not depend on whether their driving was in fact impaired. Having the required BAC of .08% or higher is enough to establish guilt.
Commercial drivers can be convicted of DWI for driving with a BAC of .04% or more. Drivers under the age of 21 years can be convicted on the basis of a BAC of .02% or more.
At the arraignment for a DWI offense in New York, the court suspends the license of any driver who had a BAC of .08% or more while the criminal prosecution is in process. The court also suspends the license of a driver who refused a chemical test pending the outcome of a Department of Motor Vehicles (DMV) hearing. If the refusal is confirmed at the DMV hearing, the DMV revokes the person’s license for one year. Eligible offenders can obtain a “conditional license” or “hardship privilege,” which allows driving in limited situations during the suspension or revocation period.
In addition, in New York, a driver whose license is revoked for refusing to submit to a chemical test must pay a $500 civil penalty.
The maximum jail sentence for a first drunk driving conviction is one year. The court can impose a fine of $500 to $1,000 in addition to a jail sentence. A driver whose BAC was 0.18% or more can face the more serious charge of aggravated DWI, which carries harsher penalties.
A person’s driver’s license is revoked for six months as the result of a first drunk driving conviction. Drivers who participate in a rehabilitation program are generally eligible for a conditional license.
In New York, a person who is convicted of DWI or DWI per se must complete a term of probation or conditional discharge. As a condition of probation, the person must install and maintain an ignition interlock device (IID) in any vehicle that they own or operate. Depending on the circumstances, the defendant will have to use the IID for a minimum of six months and possibly up to one year.
Of course, in all states, a second or subsequent drunk driving offense would result in still more harsh penalties.
Should I Consult an Attorney?
An experienced DUI /DWI lawyer can be extremely helpful to you if you have been charged with DUI or DWI. A criminal defense attorney can help evaluate the evidence against you and determine whether or not the field sobriety tests were administered correctly.
They can make sure that the equipment used to test your BAC was correctly calibrated and accurately measure your BAC. In addition, experienced criminal defense attorneys might be able to get a reduction in the penalties imposed on first time offenders.