Safest to start out on the street- a 60cc to 250cc scooter with an automatic transmission. Learn to steer and brake on the street, before adding the clutch and shift lever.
Medium safety- a 250cc Ninja, before 2008 they are uglier and cheaper.
Very little safety- a 600cc 4-cylinder supersport.
You are totally insane- a 1000cc supersport, ZX-14, Hayabusa.
"We have created a Star Wars civilization, with Stone Age emotions, medieval institutions, and godlike technology. We thrash about. We are terribly confused by the mere fact of our existence, and a danger to ourselves and to the rest of life.”
― from Edward O. Wilson, The Social Conquest of Earth.