Driving around Thailand, you may hear cars and motorbikes inexplicably beeping their horn. They usually aren’t warning of police ahead (in that case they would most often flash headlights). The beeping means you are likely about to pass a sacred shrine like the Pu Don Ho Shrine, or the hillside shrine that overlooks Sakon Nakhon's winding "snake road," just past the Namtok Kham Hom waterfall. Drivers beep their motorcycle or car horn for good luck when passing these shrines.
The Pu Don Ho Shrine (ศาลเจ้าปู่ดอนหอ) is a shrine that honors the ghost ancestors of the area around the shrine. It is a place where local villagers go to seek a blessing, or to meditate on their troubles while seeking an answer. The shrine has a spirit house with a grandfather and grandmother inside, representing the village ancestors. There is also a small pavilion with Naga guardians at the steps which houses a small statue of Phra Phrom, the Thai version of the Hindu god Brahma.
Phra Phrom is only occasionally seen at Sakon Nakhon temples, such as at Wat Song Pracharam. He is sometimes referred to as the 4 headed Buddha, and is considered especially powerful in his ability to offer protection and grant blessings. In Hindu philosophy, he is the creator god.