A Randolph man was arrested on numerous charges, including indecent exposure, at the Blue Hills Reservation in Milton on Saturday evening, State Police said. State Police found the man when a concerned citizen, visiting the area known as The Overlook with his girlfriend and two small children, reported seeing a naked man engaging in lewd activities in his vehicle. The man was identified as 55-year-old Walter V. Pimental. He was arrested on seven charges, including operating under the influence and operating a vehicle with a revoked license as a habitual traffic offender, State Police said. Pimental was arraigned on Monday in Quincy District Court, where a judge set his bail at $8,500 surety and ordered him not to drive if he is released, according to David Traub, a spokesman for the Norfolk district attorney’s office.