Phetkasem Road

Phetkasem Road (, ) or Thailand Route 4 (, ) is one of the four major highways in Thailand, along with Phahonyothin Road (Route 1), Mittraphap Road (Route 2), and Sukhumvit Road (Route 3). At 1,274 km, it is the longest highway in Thailand. It begins at Naowa Chamnian bridge in Bangkok Yai, Bangkok. It is named after Luang Phetkasemwithisawasdi, the seventh director general of the Department of Highways.