To my knowledge this is very jurisdiction specific. In a bigger city like Allentown, Reading, etc. where they have multiple holding cells and officers to man those blocks, they’ll keep them until they sober up. The vast majority of PD’s in the state and throughout the country likely don’t have such manpower so they release the person to a family member or friend so the police don’t have to babysit.

I know in several PA counties they’ll either take you home to a family member/friend or have someone pick you up if they’re too far away because most of the PDs only have a handful of people working at any given time.