If you are pulled over and caught driving under the influence of heroin, you are in a lot more trouble than someone who is just drunk. For one, the heroin is illegal, and two, most people on this drug tend to hallucinate and/or have manic episodes that cause them to behave quite erratically. You are putting more than just yourself and any passengers in your car in danger; you are putting everyone else within two miles of you in danger while you are driving. Here is what you can expect as punishment if police officers run you in for a DUI and find heroin in your system.
Felony Criminal Charge
Because the heroin was in your bloodstream, it is possible to charge you with possession. The assumption here is that you bought enough heroin to use, and that you might have a little more stashed somewhere for later. In some states, just having the drug in your system may be enough to claim "possession of an illegal substance." You could be facing a felony criminal charge along with your DUI. The judge may also order you to enter a drug rehab and detox program to deal with your heroin use/abuse.
The DUI Itself
Next, a judge will temporarily set aside the drug charges and look at your DUI. Recognizing that you were under the influence of a powerful substance, you could have killed or injured dozens, including yourself. For that you receive a criminal charge for the DUI and spend time in jail or receive a very stiff fine.
Property Damaged or People Injured
Property damaged and/or people injured results in an additional charge of "reckless endangerment." Lives and property were ruined, and you were at fault because you were driving under the influence of heroin. You will have to repay the owners for the damaged property and pay any and all medical bills for those that you injured with your car.
If you accidentally killed someone while driving under the influence of heroin, guess what? You also have a criminal charge of "vehicular manslaghter" on your hands. If convicted and sentenced (which is highly probable), you may get several years in prison, tens of thousands in fines, and little chance of parole. It just depends on the number of people you accidentally killed and the state in which you reside. Some states take heroin addiction and DUI's very seriously, and punishments are even more harsh than in other states.