The Department of Highways (DOH) is preparing to seek Cabinet approval for the proposed Nakhon Pathom–Cha-am motorway project, a 61-kilometre route valued at 54.56 billion baht, with construction expected to begin in 2027.
According to DOH Director-General Piyapong Jiwattanakulpaisan, the project aims to improve transport connectivity between Nakhon Pathom, Ratchaburi, and Samut Songkhram provinces. It will also serve as a key link to Phetchaburi and Prachuap Khiri Khan, providing an alternative to the heavily used Phetkasem Road (Highway 4) and Rama II Road (Highway 35).
The proposal will first be reviewed by the Ministry of Transport before being submitted to the Cabinet for approval by January 2026. Once endorsed, the DOH will begin the land expropriation process by late 2026, covering approximately 5,340 rai across the three provinces. A royal decree will then be issued to formalise the process, with compensation expected to take six to eight months.
Project structure and investment
The 54.56-billion-baht budget includes 40.16 billion baht for civil works and 14.4 billion baht for land acquisition. Construction will be divided into two main phases.
Phase 1 covers the Nakhon Pathom–Talad Chinda section (11 km), with a budget of 10.51 billion baht. The work will be funded from the motorway toll fund and is expected to take three years, starting in 2027.
Phase 2 covers the Talad Chinda–Pak Tho section (50 km) at a cost of 29.65 billion baht. Budget allocation for this phase is expected in 2028, with construction also taking three years. The full route is projected to open to traffic by 2032.
Route connections and future expansion
The motorway will begin at the Srisathong checkpoint in Nakhon Chai Si District, Nakhon Pathom, linking with the M81 Bang Yai–Kanchanaburi motorway. It will connect with Highway 338 (Borommaratchachonnani Road) and Highway 4 (Phetkasem Road), before terminating at a junction with Highway 35 (Rama II Road) in Pak Tho District, Ratchaburi.
While the initial proposal focuses on the Nakhon Pathom–Pak Tho stretch, the long-term plan extends the route to Cha-am. However, the Pak Tho–Cha-am section remains under review following local opposition in parts of Phetchaburi province. The Ministry of Transport has instructed the DOH to assess alternative routes by 2026 before advancing this section.
Once completed, the Nakhon Pathom–Cha-am motorway will form an essential corridor between central and western Thailand, easing traffic congestion and reducing travel times for both freight and passenger transport heading toward the southern provinces.
