Obviously a little hub motor in front is not the same thing, but they can still be problematic on corners and on wet pavement, especially if they are more powerful. (treehugger.com)
The consensus seems to be that front hub motors are the easiest and most economical, but keep them small. (treehugger.com)
[48] It is naturally available on electric bicycles with direct - drive hub motors. (en.m.wikipedia.org)