A vehicle classed as a motorized bicycle in Iowa can not exceed 30mph on flat ground.
Depending on your age you may need a special moped permit to ride a motorized bicycle on public roads in Iowa.
14 -15 years old: Moped Permit AND Rider Education Course
16 - 17 years old: Moped Permit OR Intermediate License
18 years and older: Moped Permit OR Drivers License
A motorized bicycle must be registered in Iowa the same way as a motorcycle is registered.