Is Driving Under the Influence Always Alcohol-Related?

The penalties for driving while under the influence in Pennsylvania are severe. Even if you are later found not guilty, you may still have to pay expensive court costs, attorney’s fees, and have to deal with the stress and anxiety of the whole ordeal. And while many people believe that DUI only applies if you are under the influence of alcohol, DUI also includes any other controlled substance that can impair your ability to operate a motor vehicle safely.

Alcohol-Related DUI

In Pennsylvania, if you are found to be operating a motor vehicle with a blood alcohol content (BAC) of .08 or higher, then you can be convicted of driving while under the influence of alcohol. This limit applies regardless of whether you were pulled over for suspicious driving or for some other reason. For example, an arresting officer may require that you submit to a Breathalyzer test after stopping you for something unrelated, such as having a broken taillight. If your BAC is over .08, then you’re going to jail.

You may be surprised to know that you can be convicted of DUI at lower blood alcohol levels if you are pulled over for driving erratically, such as driving too slow, too fast, not staying in your lane, making sudden stops for no reasons, or failing to obey traffic signals. While you’re BAC may not be over the legal limit, the argument is that your driving was nonetheless impaired by the presence of alcohol.

For drivers under the age of 21, Pennsylvania has a zero tolerance law. If you are under 21 years of age, you are not permitted to operate a motor vehicle with any measurable level of alcohol in your system. Persons under 21 who are found to have a blood alcohol level of .02 or higher are considered to be driving while under the influence. Underage drinkers may also have their driver’s license suspended, even if they are not driving.

Driving Under the Influence of Drugs

While alcohol-related DUIs are most common, the penalties for operating an automobile under the influence of drugs are just as severe. Also known as DUI(D) or drugged driving, a person driving in Pennsylvania is guilty of DUI if he or she drives (1) with any amount of a Schedule 1 controlled substance in his or her blood; (2) with a metabolite of a schedule 1 substance in his or her blood; (3) under the influence of a drug or combination of drugs that impairs his or her ability to safely operate the motor vehicle; or (4) under a combination of drugs and alcohol that impairs his or her ability to safely operate the motor vehicle.

Something to note here is that the metabolite of a controlled substance may be present in your blood even though you were not under the influence of that drug while operating your vehicle. Because of this, there is a certain threshold for the concentration of drug-related metabolites before the test can be introduced into evidence against you. Also, some drugs stay in your system longer than others, and these facts can be used to contest whether certain metabolites could have affected your driving at the time of your arrest.

DUID charges sometimes arise when a breath test doesn’t register over .08, but the arresting officer still suspects that the driver is under the influence of another substance. Some law enforcement agencies in Pennsylvania also have Drug Recognition Evaluators who participate in DUID investigations. These Drug Recognition Evaluators are trained to check for evidence of drug use, including:

  • Increased blood pressure
  • Pulse rate
  • Dilated pupils
  • Injection marks; and
  • Other evidence of drug use.


Like alcohol-related DUIs, drug-related DUIs are susceptible to inaccurate readings and may only be supported by circumstantial evidence. Depending on the facts and circumstances of your arrest, there may be a number of defenses available to you to have your charges reduced or dismissed all together. An experienced DUI attorney will be able to advise you how to best proceed with your case.

Impaired Driving Legal Defense

Being charged with driving under the influence of drugs or alcohol is a very serious criminal offense. In addition to the possibility of jail time and losing your license, you will also have to pay expensive fines and may be required to perform community service, attend alcohol education classes, and more. Even if you are ultimately found not guilty of DUI, you can still lose your license if you don’t take immediate action following your initial arrest.

If you or someone you love has been arrested for DUI, contact The Law Offices of Steven E. Kellis today to schedule a free consultation.