Phnom Penh-Sihanoukville Expressway

What the road is and where it runs

The expressway covers about 187.05 km between Phnom Penh and Sihanoukville. It starts on the western edge of the capital, where it connects to the city ring road, then heads southwest through Kandal, Kampong Speu and Koh Kong provinces before finishing in Preah Sihanouk province, close to the port area of Sihanoukville.

It is a dual carriageway with two lanes each way plus emergency lanes, about 24.5 metres wide. Along the route there are several interchanges, rest areas, maintenance centres, bridges and service facilities. Posted speed limits run from 80 to 120 km/h, depending on vehicle type and conditions.

Time saved against National Road 4

Until the expressway opened, the usual route was National Road 4, a two-lane highway of roughly 230 km. In heavy traffic that drive could take 4 to 6 hours or longer.

By car on the expressway, expect around 2 to 2.5 hours, depending on how fast you drive and how busy it is. NR4 remains toll-free, which is why some drivers still use it.

Tolls and how to pay

The expressway is a distance-based toll road, charged per kilometre according to vehicle class. The 2025 rates for the full one-way trip of about 187 km were roughly:

• Passenger cars: about $0.08 per km, around $15 one-way
• Small trucks and buses: about $0.16 per km, around $30 one-way
• Large trucks and heavy vehicles: about $0.40 per km, up to around $75 one-way

During the first year after opening (2022-23) discounts of about 20% applied, and early estimates put the average full-route cost for a car at $12 to $24. The standard rates above are probably what applies now, but check before a long haul.

You can pay manually at toll booths, through a mobile app, or with electronic ETC/ANPR systems, with no extra hardware charge. Because there are several entrances and exits, you pay only for the stretch you actually use.

Who can use it

Not every vehicle is allowed. Motorcycles under 500 cc are typically barred, as are vehicles over certain size and weight limits. Larger commercial vehicles need to meet specifications such as a maximum height of about 5.2 m and a maximum weight of about 40 tonnes.

Construction and background

The road was built by the China Road and Bridge Corporation (CRBC) under a Build-Operate-Transfer public-private partnership, and is run through its Cambodian subsidiary. The cost was about US$1.9 to 2 billion. Work began in March 2019 and finished in September 2022, with the official opening for public use later that year.

Why it matters

Faster freight between Phnom Penh and the port cuts logistics costs, and the road improves access for tourism and helps draw investment along its corridor. The tolls are a sticking point, though: some small transport operators and drivers still choose the slower NR4 to avoid the fees.