When someone is injured in Pennsylvania by a drunk driver or someone else who is intoxicated, the victim and family may not realize that the person who provided the alcohol could be liable for the damages as well. Laws that allow people to hold a bar or restaurant responsible for an intoxicated customer's actions are usually called dram shop laws, a name that comes from an 18th-century term for a place that sells alcohol.
In Pennsylvania, establishments that sell alcohol are not automatically liable for wrongdoing by one of their customers who was drinking. In fact, Pennsylvania law explicitly clears them of any liability with only a few exceptions. For example, if the business sold alcohol someone who was visibly intoxicated or a minor, then it might be possible to sue them for this.
Moreover, the dram shop laws make the business liable for any damages that a customer does to a third party only if they provided alcohol to someone who was "visibly intoxicated." For example, if a sober man bought a bottle of vodka, drank it and caused damage to someone else while intoxicated, the shop that sold him the bottle would not be liable for providing the alcohol. However, if the man was already drunk when he bought it, then this might be considered over-serving a customer.
In most cases, for plaintiffs to receive compensation under a dram shop law, they must show evidence that the business provided alcohol to the person who caused the damages, that the alcohol caused the damages in some way, and that the person was intoxicated when they were provided it. In Pennsylvania, liability applies equally whether the alcohol was sold or given to the customer.
Source: NCSL.org, "DRAM SHOP CIVIL LIABILITY AND CRIMINAL PENALTY STATE STATUTES", August 13, 2014