carseats on tour buses...
I understand your concern about buses and the lack of seat belts. I don't have an easy answer for you.
I've done a lot of research about school buses, which also rely on "compartmentilization" to protect the occupants. On buses, this system works quite well, especially for school aged children. For young children, I highly recommend using a regular carseat, secured by a seat belt or cam wrap. However, all the occupants on school buses continue to be safer as a group then similar occupants in cars and light trucks. In fact, they are considered to be 7 time safer.
So what is the difference between a school bus and your tour bus? I don't know. School buses are subject to many regulations about rollover strength, breaks, color, behavior and so on. Some of the good crash figures come from the fact that buses are so large that cars dont' stand a chance against the bus. When a car impacts a bus, the crash forces hit at the level of the bus occupants' feet, not heads. Buses tend to travel at low speeds: your tour bus may not. And so on.
So what do I recommend? Well, I recommend that the tour bus properly install belts for you to use with your carseat. Is this going to happen? I doubt it. Ask though.
Should you take the tour bus or drive your own car? Probably take the bus. Yes, I'd like to see your child in a carseat, but still, buses rate so much safer than cars.
What can you do to make sure you are as safe as possible on the bus? Stay properly seated, facing forward. That is how the bus is designed to protect you. Make sure there is enough room to sit properly in your row, without hanging out. Take special care when entering or exiting the bus. That is where 3/4 of the problems occur with school buses. The other big area of concern with school buses is train crossings. I guess since trains are one of the few things as big as buses (except semis, of course).
If you do these things, you are not guaranteed a safe ride, but statistically I supect you'll be better off than buckling up properly in your car.
Have a great trip!
Toby, CPS tech