Most people are aware of the dangers of drunk driving, but understandable errors in judgment can result in a person being arrested for driving under influence of alcohol or controlled substance (DUI) in Pennsylvania.
For many alleged offenders, these incidents represent their first encounters with law enforcement and their introduction to the criminal justice system.
Under Pennsylvania Consolidated Statute Title 75 § 3802, a person can be charged with this crime if he or she drives, operates, or is in actual physical control of the movement of a vehicle after imbibing a sufficient amount of alcohol or certain controlled substances.
The violations involving controlled substances include any amount of a Schedule I controlled substance or any amount of a non-prescribed Schedule II or Schedule III controlled substance in the alleged offender's blood.
It is also illegal for a driver to be under the influence of a solvent or noxious substance, a drug or combination of drugs, or the combined influence of alcohol and a drug or combination of drugs.
While an alleged offender may be arrested for appearing to be under the influence of a drug or having any amount of a controlled substance in his or her system, there are three different levels of intoxication in regards to alcohol.
These are determined by the alleged offender's breath or blood alcohol concentration (BAC):

• General Impairment is a BAC of 0.
  08 percent or higher but less than 0.
  10 percent
• High rate of alcohol is a BAC of 0.
  10 percent or higher but less than 0.
  16 percent
• Highest rate of alcohol is any BAC that is 0.
  16 percent or higher

There are different BAC standards for certain drivers though.
School bus drivers, school vehicle drivers, and drivers under the age of 21 can be charged with DUI for a BAC of 0.
02 percent or higher, and commercial drivers may be charged with this offense if they have a BAC of 0.
04 percent or higher.
BAC measurements are typically obtained during chemical tests such as a breath test (Breathalyzer).
Most people agree to perform these tests because they believe that they are obligated to under the Commonwealth's implied consent law that states every driver automatically agrees to comply with requests for these tests just by receiving their Pennsylvania driver's licenses.
However, motorists should know that they have the right to refuse these tests.
While failure to submit to requested tests will automatically cause a person's license to be suspended for one year, it will also make it more difficult for a prosecutor to prove any alleged intoxication.
Agreeing to and failing a BAC test can lead to a conviction and being sentenced the following penalties:

• Pay a fine of $300 for alleged offenders convicted of general impairment, a fine of $500-$5,000 for alleged offenders convicted of high rate of blood alcohol or any school bus drivers, school vehicle drivers, drivers under the age of 21, or commercial drivers, or a fine of $1,000-$5,000 for alleged offenders convicted of highest blood alcohol or controlled substances
• Attend an alcohol highway safety school
• Comply with all drug and alcohol treatment requirements relating to drug and alcohol assessments and mandatory sentencing

In addition to the penalties above, alleged offenders convicted of general impairment can be sentenced to a mandatory minimum probation term of six months, alleged offenders convicted of high rate of blood alcohol or any school bus drivers, school vehicle drivers, drivers under the age of 21 can be sentenced to a minimum of 48 consecutive hours in jail, and alleged offenders convicted of highest blood alcohol or controlled substances can be sentenced to a jail term between 72 consecutive hours and six months.