Some alternatively fueled engines like propane or gasoline may need to be replaced two to three times during the normal lifecycle of a school bus. Clean-diesel engines, on the other hand, are built to last 15-20 years. The difference in engine life lies in how engines are built.
Battery-charged vehicles typically have a driving range of 70-100 miles, and some can go up to 265 miles before needing to be recharged (diesel buses have an average range of 690 miles).
If a school bus had an 80-gallon tank and operated with a fuel economy of about 6 miles per gallon, it could travel about 480 miles. According to the U.S. Department of Energy, the average school bus travels 12,000 miles per year4.
Issues with the routeOften, the bus goes on diversion, winding its way around back streets. But this isn't always feasible. Perhaps the roadworks come too close to the end of the route, and it's logical to terminate early.
Propulsion. The most common power source since the 1920s has been the diesel engine. Early buses, known as trolleybuses, were powered by electricity supplied from overhead lines.