Construction Begins on M9 Motorway Western Ring Road Main Route Closed April 18—Check Traffic Diversion Points Here

The Department of Highways is preparing to close the main lanes of the Western Ring Road (Kanchanaphisek Road) between Bang Bua Thong and Lat Lum Kaeo starting 18 April 2026 to fully commence construction of the M9 Motorway. This aims to alleviate traffic congestion and enhance the country's logistics system, with recommended detours for drivers' convenience.

D-Day 18 Apr 2026: Main lanes closed to begin M9 Motorway construction.

The Department of Highways (DOH), via the Construction Division 1, reports progress on Highway No. 9 development (the Western Outer Ring Road of Bangkok or Kanchanaphisek Road). It plans to close the mainline lanes in Section 1 between Bang Bua Thong and Lat Lum Kaeo, covering a total distance of 13.775 kilometers.

From 18 April 2026 onward, traffic lanes between km 50+800 (before the HomePro Bang Bua Thong branch) and km 64+575 will be closed 24 hours a day in both inbound and outbound directions to prepare the site for constructing a new road structure meeting expressway standards (motorway).

Drivers can use the parallel frontage roads as alternatives. The Department of Highways has preemptively expanded these routes to three lanes per side to handle traffic volume and reduce congestion buildup.

Upgrading the Western Ring Road for seamless network connectivity.

The Western Kanchanaphisek Road has been in use since 2000. It now must accommodate increased traffic, especially heavy trucks, which affect freight transport costs. The Cabinet approved the construction of Highway No. 9 Motorway from Bang Bua Thong to Bang Pa-in, with a civil works budget of 15.862 billion baht, to upgrade the route to a fully controlled-access motorway.

Features and highlights of the M9 project.

• Road surface improvements. Concrete pavement with 6 lanes total (3 lanes per direction).
• Coverage area. From Bang Bua Thong Interchange in Nonthaburi Province to Bang Pa-in Interchange in Phra Nakhon Si Ayutthaya Province.
• Four entry and exit points. Bang Bua Thong Toll Plaza, Lat Lum Kaeo Toll Plaza, Sam Khok Toll Plaza, and Bang Sai Toll Plaza.
• Toll collection system. Automated barrier-free system (M-Flow).
• Impact on the public. Construction will occur entirely within the existing right-of-way. No land expropriation will be required.

The project is expected to open in 2030, completing the outer ring road network and connecting smoothly with other major motorways such as M81 (Bang Yai - Kanchanaburi), M82 (Bang Khun Thian - Ban Phaeo), and M6 (Bang Pa-in - Nakhon Ratchasima).

Recommended detours to avoid traffic toward Bang Pa-in.

For convenient travel, the Department of Highways recommends alternate routes for those traveling from Bang Bua Thong District to Bang Pa-in District as follows:

1. Use Highway No. 345 heading toward Pathum Thani Province.
2. Turn onto Ratchaphruek Road (Provincial Road 3021).
3. Connect to Highway No. 3111 (Pathum Thani – Sam Khok – Sena route) at Santi Suk intersection.
4. Drive toward Sam Khok District to rejoin Kanchanaphisek Road (M9) at Sam Khok Interchange (km 71+300), then continue normally to Bang Pa-in.

The Department of Highways apologizes for any inconvenience and urges drivers to plan ahead, drive carefully, strictly follow signage, and contact the DOH hotline at 1586, toll-free across all networks, available 24 hours a day, for more information.

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