I Have a trailer hitch mounter bike rack, its the bees knees in bike transportation, only problem is that it makes my car about 2 inches lower when the 2 motorized bicycles are loaded. So i scrape the ground coming out of driveways. but its no biggie. THe one i have cost me 150 and can hold 3 regular bikes upto 100lbs, i can load 2 motorized bicycles on it safely.
here is a shopping list of places that sell them