A moped (/ˈmoʊpɛd/ MOH-ped) is a small motorcycle, generally having a less stringent licensing requirement than motorcycles or automobiles because mopeds typically travel about the same speed as bicycles on public roadways. Strictly speaking, mopeds are driven by both an engine and by bicycle pedals, but in common usage and in many jurisdictions the term moped is used for similar vehicles including a scooter, though this is quite erroneous. Mopeds occasionally resemble powered bicycles, more commonly called a motorized bicycle, though since ca. 2006 there has been a glut of engine kits shipped from China (although Tanaka had offered drive kits since the 1960s) designed in theory to transform a standard bicycle into a motor vehicle but lacking the benefit of proper brakes and lighting. In addition, the added stresses can cause the rear rim to warp, and the spokes to break, and if the engine is the least bit out of alignment the drive chain will come off the drive sprocket, causing the rim to warp and the spokes to break, as well as lodging the chain in the chainstay and causing injury to the operator. Some mopeds are of a step-through type design, while others are step-over, or top tank, designs, having a motorcycle-like frame, including a "backbone" and a raised fuel tank (known as a top tank among moped enthusiasts), mounted directly between the saddle and the head tube. Most are similar to a regular motorcycle, only having the addition of pedals, in which the rider can both manually power the vehicle through a bicycle-like crankset in addition to a small displacement engine. Although mopeds usually have two wheels, some regions classify low-powered three- or (rarely) four-wheeled vehicles as a moped. Many(US ?)states have laws on the books that anyone convicted of a DUI cannot legally operate any motor vehicle powered by gasoline for the entire length of their sentence.