Do you need a motorcycle license to operate a 150cc scooter in California-or is a Driver's License enough?

Yes, from the research I have found online (im looking to buy one myself) any scooter/moped over 50cc requires the motorcycle endorsement, insurance, and a helmet in michigan. Source:...

i just purchased a 150cc scooter in Illinois on sept 27, 2008. according to the dealer, as of January 1, 2008; any motor scooter or cycle that can travel at 30mph or faster is required to have a...

Yes, I just bought a 150cc and checked at the courthouse.

Not in the UK

I don't know about every state, but in most, no. You can get just a motorcycle license.