The advantage of busways is that they’re a lot cheaper to build than trains. You just need some paint on pavement to build a dedicated bus lane. All you have to really build are some nice bus stops. The big problem with trains is vertical and horizontal alignment. You can’t just lay train tracks on top of an existing road system. Cars and buses can handle much greater slopes and perform much steeper turns than trains can.
For example, you can make a busway over an existing road bridge, without any need to rebuild the bridge itself. But you can’t just slap some train tracks on an existing road bridge, as the train would be unable to make it up the slopes designed for car traffic.
It really depends on the location I guess. I ride the bus a lot in my city. And the bus drivers here do a lot more than just drive the bus. Their most important secondary duty is helping users of wheelchairs and other mobility devices. The buses have wheelchair ramps that fold down, which the drivers manually operate. Then once on the bus, a front section of seats will fold up, and there is a system to strap a wheelchair down securely. It is the bus driver that does this.
Now, one area automated buses could really help would be expanding the pool of potential drivers. Our system has a hard time recruiting new drivers, as a CDL (commercial drivers license) is required. And people with such a license can usually make better money driving trucks for for-profit businesses. So it’s really hard to get, train, and retain bus drivers, as few people are actually qualified to drive a bus.
So in our city, we would still need an employee onboard to help with these secondary duties. However, with an automated bus, they could be done by anyone. Instead of a driver with a CDL, we could hire some college kids to ride around the city in the auto buses. They could offer assistance when needed, but spend the majority of their time just working on their studies. As such, they could be hired at a very affordable cost to the city.