That's probably because buses have more interaction with pedestrians, both due to people getting in and out, but also, operation in urban areas where there's a lot of pedestrian traffic.
A truck in this discussion is a car, not a real truck. A bus is not comparable to a car. Compare a bus to a real truck. A motorcycle will in every single statistics drive faster on average than a car. I'm not saying your point is wrong but it is at a minimum like a click bait title.
Re:2022 Ford F-150 Lightning
by brandonmenc on Friday May 21, 2021 @07:15PM
(#27241112)
"Passenger cars and light trucks (vans, pickups, and sport utility vehicles) accounted for 46.1% and 39.1%, respectively, of the 4875 deaths, with the remainder split among motorcycles, buses, and heavy trucks."
If you count crossovers as cars, trucks make up like 35% of auto sales and account for 39% of pedestrian deaths.
There is nothing to be concerned about.
https://www.statista.com/statistics/276506/change-in-us-car-...
"Compared with cars, buses were 11.85 times and motorcycles were 3.77 times more likely per mile to kill children 0–14 years old. Buses were 16.70 times more likely to kill adults age 85 or older than were cars."
https://injuryprevention.bmj.com/content/11/4/232