Phnom Penh - Sihanoukville Expressway | Cambodia
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Length and Route
The expressway stretches for about 187.05 km from Phnom Penh to Sihanoukville, running southwest through Kandal, Kampong Speu, Koh Kong, and finally Preah Sihanouk provinces. It begins on the western side of Phnom Penh, linking with the city's ring road, and ends near Sihanoukville's port facilities.
Construction and Features
Built under a Build-Operate-Transfer (BOT) public-private partnership model by the China Road and Bridge Corporation (CRBC) and operated through its Cambodian subsidiary, the project cost approximately US $1.9 - 2 billion. Construction began in March 2019 and was completed in September 2022, with an official opening for public use later that year.
The road is a four-lane, dual carriageway, with two lanes in each direction plus emergency lanes, designed for high-speed travel. Its width is about 24.5 meters, and it includes several intersections, rest areas, maintenance centers, bridges, and service facilities along the way. The posted speed limits range from 80 km/h to 120 km/h, depending on vehicle type and road conditions.
Travel Time Benefits
Before the expressway, the main route between Phnom Penh and Sihanoukville was National Road 4 (NR4), a roughly 230 km two-lane highway that could take 4-6 hours or more in heavy traffic. The new expressway cuts travel time roughly in half, with typical journeys by car taking around 2-2.5 hours, depending on speed and traffic.
Toll System and Fees
Unlike the old NR4, which is toll-free, the expressway operates as a distance-based toll road. Toll charges vary by vehicle class and distance traveled, calculated per kilometer. Current pricing (2025 rates) for a full one-way trip of ~187 km is approximately:
- Passenger cars: about $0.08 per km → ~$15 one-way
- Small trucks / buses: ~$0.16 per km → ~$30 one-way
- Large trucks or heavy vehicles: ~$0.40 per km → up to ~$75 one-way
In the first year after opening (2022-23), discounted rates were offered (about 20 % off), and earlier estimates placed the average per-car cost for the full route around $12-$24. Today the toll system has likely transitioned to its standard rates.
Tolls can be paid manually at booths, by mobile app, or via ETC/ANPR electronic systems with no extra hardware charge, and there are multiple entrances/exits along the route so users pay only for the distance they travel.
Vehicle Access and Restrictions
Not all vehicles may use the expressway: motorcycles under 500 cc and vehicles above certain size/weight limits are typically restricted. Larger commercial vehicles must meet specifications (e.g., max height ~5.2 m; max weight ~40 t) to ensure safety and traffic flow.
Economic and Social Impact
The expressway is seen as a major economic enabler, facilitating faster movement of goods and people between Cambodia's largest city and its key port. It supports reduced logistics costs, improved connectivity for tourism, and helps attract investment along its corridor. However, toll costs have been a concern for some small transport operators and drivers who sometimes choose the slower NR4 to avoid fees.
The Phnom Penh-Sihanoukville Expressway is a transformative infrastructure project in Cambodia, offering a faster, safer, and modern road connection at a cost that balances user fees with efficiency gains compared to the traditional route.