No , bus lanes will not work,,, unless all buses are equipped with bull-bars in front, and are allowed to use them .

From the Cambodian government news agency:
Over 8 Million Passengers Use Public Bus Service in 2019
AKP Phnom Penh, February 25, 2020 --

Public bus service welcomed 8,265,107 passengers in 2019, of them 5,474,674 were served free of charge, according to the report from Phnom Penh municipal administration.

The bus service operates within the geographical locations of Phnom Penh, and between Phnom Penh and the provinces during special occasions such as Khmer New Year and Pchum Ben Festival.

Beginning its operation in 2014, the public bus service has gradually increased its passengers, and as of now an average between 28,000 and 30,000 passengers is using the transportation mean.

The move contributes vitally to addressing traffic congestion in Phnom Penh, according to the report.
There are currently 235 city buses –donated by Japan and China – operating along 13 lines in Phnom Penh.

Article in Khmer by Suos Samrith
Article in English by Lim Nary
https://www.akp.gov.kh/post/detail/26609