On page 111 of your reading material there is a problem that requires you to calculable the average speed for a daylong bus trip?

47.3 miles per hour

Highway or surface streets? On the highway they can go 65, unless it's a school bus, 55, and on the streets, the same as a car. There is more caution on turns because of the height, and slowing...

40 km/hr in the cities

25mph that sure is slow but that is the top speed

42.4mph