I realized I had just assumed that electric buses were significantly heavier than ICE buses. They can be much heavier; however, using an aluminum frame or smaller batteries (if you don't need the range), can bring the weight down considerably. It's hard to get exact weights because the weight varies by configuration.
I was mostly thinking of efficiency issues. But apparently, they have lead to issues with road wear in Indianapolis[0], although this may in part be due to poor planning on the transit agency or public works' part.
Huh I hadn't realized this might be an issue; thanks for the info. I know roads are rated for weight but I didn't think electric buses might have been so heavy to generally exceed it.