Thailand has initiated a major infrastructure upgrade along Highway 37, also known as the Cha-am Bypass, to alleviate regional traffic congestion, enhance safety, and promote tourism and economic development along the Gulf of Thailand. The project, led by the Department of Highways, began in 2023 and is scheduled for completion in 2026.
The development stretches approximately 50 kilometers, connecting Cha-am in Phetchaburi province to Pranburi in Prachuap Khiri Khan. With a budget of 7 billion baht allocated over three fiscal years, the plan includes expanding the current four-lane road to six lanes, the construction of six grade-separated interchanges, and the addition of 17 U-turn points.
Key improvements involve building three 3.5-meter-wide lanes in each direction, divided by a central concrete barrier, with enhanced shoulders for safety—2.5 meters on the outer side and 1 meter on the inner. These upgrades are designed to accommodate increasing traffic volume, which stood at around 29,000 vehicles per day in 2020 and is projected to rise to 35,000 by 2026 and reach approximately 53,000 by 2044, according to official projections.
The revamped route will traverse significant areas, starting from the Cha-am interchange on Phetkasem Road, passing landmarks such as Silpakorn University, Wat Huai Mongkol, and the Hua Hin District Office, before reconnecting with Phetkasem Road in Pranburi. It plays a strategic role for daily commuters, logistics carriers, and tourists moving through the Cha-am, Hua Hin, and Pranburi districts.
The initiative is aligned with Thailand’s 13th National Economic and Social Development Plan (2023–2027), which prioritizes transport connectivity in upper southern Thailand. Safety enhancements include a mix of flyovers, underpasses, and culverts to support smooth traffic flow and facilitate crossings for small vehicles and wildlife. The design also incorporates aesthetic elements such as landscaped junctions and decorative concrete features.
Construction is already visible near several points, including areas around the Springfield Golf Course and along the Cha-am–Hua Hin corridor. Upon completion, the upgraded highway is expected to significantly reduce congestion and accidents while providing a critical boost to the region’s tourism and agricultural sectors.
Officials from the Department of Highways and local authorities have overseen progress on the site. Reports on the project’s advancement have appeared in publications such as Bangkok Post and Hua Hin Today.
