I'm not assigned to any of the programs involved, so I only catch a little bit of information about electric truck programs at my employer. But what I do know, is that we are working big time on developing a practical electric school bus. The technology is being developed with the resources of our partner Traton which is VWs spinoff of their truck companies MAN and Scania. Similar to the situation with propane, electric seems best suited to fleets that make local runs and then return to a central location where they are parked for long periods and can be charged, or in the case with propane, refueled from their propane stations as there are few propane stations available to the public.
Despite all the resources and technology available, my understanding is the prototype school busses have a very short range. It sounds like we have a long way to go before they are practical for school districts to use in their fleets.
Both Tesla and another company Nikola claim to have over the road electric truck tractors about ready to go. Until I see it happen, I'm skeptical that their claims aren't hyped up exaggerations to impress potential investors.
As for electric cars, their charge times vary exponentially as to what charging station is available. A local car guy got a model S and was telling us a 480 volt Tesla supercharging station can fully charge a car fairly quick, 75 minutes for a 100% charge. If someone has a 220 charger installed at home for their Tesla, a 100% charge takes 9 hours. Of course, less than 100% charge takes less time. My memory on times is vague so maybe someone with better Tesla knowledge can correct my times?