PHNOM PENH, Cambodia — This city of nearly two million people has many of the amenities of a modern metropolis — broadband Internet, automated teller machines and fancy restaurants, to name a few. But until this month, the capital of Cambodia had no public transportation system. To get around, residents had to inure themselves to perilous rides on motorcycle taxis or dust-smothered commutes in open three-wheeled tuk-tuks.

Now, in an experiment underwritten by the Japanese government, Phnom Penh is giving the relatively alien concept of public city buses a try. Ten buses are making their way up and down Monivong Boulevard, one of the city’s main thoroughfares, for a month to see if they catch on with Cambodians.

Egami Masahiko, representative of the Japan International Cooperation Agency, said that with Cambodia’s economy growing steadily and the streets of Phnom Penh choked with traffic, the timing was right. Mass transit, he said, is “fundamental infrastructure for a modern city.”

Since the buses began running Feb. 5, curious residents have been climbing aboard just for a test ride.