The LEGAL definition of a Moped and Scooter are frequently very similar... if not the same. In CA we have power-driven cycles and motorcycles
A motorcycle is a vehicle whose motor displaces more than 150 cubic centimeters and has a seat or saddle for the use of the rider. It is designed to travel on not more than three wheels in contact with the ground and weighs less than 1,500 pounds.
A motor-driven cycle is a motorcycle whose motor displaces less than 150 cubic centimeters. (no mention of pedals at all) This is the 50 to 149 cc scooters we think of.
What is a moped or motorized bicycle?
* There are two types of motorized bicycles, defined in the California Vehicle Code (VC) Sections 406(a) and 406(b).
* Section 406(a) VC refers to a moped or motorized bicycle as any two or three wheeled device having fully operative pedals for propulsion by human power, or having no pedals if powered solely by electrical energy, has an automatic transmission, and a motor which produces less than 2 gross brake horespower and is capable of propelling the device at a maximum speed of not more than 30 miles per hour on level ground.
* Section 406(b) VC refers to a motorized bicycle as a device that has fully operative pedals for propulsion by human power and has an electric motor that:
o Has a power output of not more than 1,000 watts;
o Is incapable of propelling the device at a speed of more than 20 miles per hour on level ground; and
o Is incapable of further increasing the speed of the device when human power is used to propel the motorized bicycle faster than 20 miles per hour.
What is a motorized skateboard or motorized scooter?
* Effective 1/1/2005, a motorized scooter is any two-wheeled device that has handlebars, has a floorboard that is designed to be stood upon when riding.
* May have a driver seat that does not interfer with the ability to stand and ride and may also be designed to be powered by human propulsion.
* Powered by electricity or other source.
Driver's License Requirements
Motorized scooter
Effective 1/1/2005, a Class C driver license or driver permit is required.
Motorcycle, motor-driven cycle, motorized bicycle/moped (Section 406(a) VC)
* Must obtain an M-1 or M-2 endorsement on a driver's license.
* M-1 allows the driver to operate a motorcycle, motor-driven cycle and moped
* M-2 allows for operation of a moped or motorized bicycle only.
* To obtain an M-1 or M-2 endorsement, the driver must:
o Pass the appropriate written exam
o Pass riding skills test (DMV will accept certificate of competence from an approved novice motorcyclist training program instead of skills test, such as the California Motorcyclist Safety Program).
o If the individual is under 21 years of age, mandatory successful completion of a Basic Rider education course approved by the CHP is required, such as the Basic Rider course available through the California Motorcyclist Safety Program.
Motorized Bicycle (Section 406(b) VC)
* Driver's License not required but rider must be at least 16 years of age.
You will notice that as many countries there are, there are as many definitions.
In Croatia (translation of the Road and traffic safety law):
1. Moped is a passenger vehicle that has two or three wheels powered by engine whose displacement is up to 50 cc and that cannot develop speed faster than 50 km/h on a straight road, and can transport only one person.
2. Scooter is a passenger vehicle with twho wheels whose purpose is transport of one or two persons.
In Croatia you need driver's license to drive anything including a freakin' bicycle.
You can drive a bicycle if you are older than 14 and pass just written traffic rules exam.
For mopeds, scoots, motorcycles and cars, you need a real driver's license and exam consists of written test (quite detailed), 20 hours of driving with instructor (for 2-wheelers) or 40 hours of driving (for cars) and then road exam performed by Croatian Auto Club. (local version of American AAA).
You can drive mopeds, scooter and motorcycles up to 50 cc slower than 50 km/h when you are 14.
You can drive up to 125 cc scooters and motorcycles when you are 16.
You can drive >125 cc 2-wheelers of all sorts and cars when you are 18.
You are not allowed to drive motorcycles >34 hp and cars >100 hp in the first few years regardless of your age.
Quads and ATVs are in the separate category but same rules and limitations apply as for 2-wheelers in regard to speed, displacement, age and other limitations.
p.s. It will be interesting to notice that if you pass both written exam and road test in first attempt, the whole story (lessons in theory, written exam, lessons in emergency medicine that lasts for three days - mandatory here, 40 hours of driving and then test with state tax) costs around 1500 US$, or 50 % more than average monthly net salary. Around 1000 US$ for motorcycle license.