Before COVID travel to Cambodia was increasing as it became even easier to travel to the country. As tourism grew, things like roads started to improve which increased the use of buses, taxis, and motodrop (known as Moto's) as using the roads were more comfortable without all the pot holes. As more people started driving it even lead to an increase in the cost of flying as driving became the preferred mode of transportation. The one down side too is that people are driving at faster speeds so while it was rare to hear about large accidents, they are starting to become more normal.
The buses in Cambodia are usually mini or large, well kept coaches. As tourist dollars pour into the country, bus companies are now improving and upgrading their vehicles because they are all in competition with each other so the best equipment makes the most money. Buses are a great way to travel from country to country as well because that is all they do so crossing the boarder is extremely quick and easy unless your bus arrives at the same time as a few other buses then things will slow down.
Motodrops aka Moto's aka Tuk Tuk are some of the most aggressive drivers in town and they are even aggressive when it comes to trying to get a tourist into their vehicle. With app's like Grab being used in the city, if you hire one of these Motodrops right off the street instead of through the app, you will find that you are ripped off due to the massive price difference.