Car registration helps primarily by assigning vehicle ownership / plate issuance, but indirectly with insurance, taxes, inspections & maintenance logging, crash

Car registration helps primarily by assigning vehicle ownership / plate issuance, but indirectly with insurance, taxes, inspections & maintenance logging, crash records, ticketing, tracking stolen cars and parts, and more. Cars are expensive, deadly and ubiquitous and much of the regulation around them was written in blood. When you write "bike" I'm not sure if you mean bicycle or motorcycle. Most places, motorcycles which will be driven on public roads do require registration. I expect that bicycles don't require registration because they don't kill as many people who are not the rider, so nobody has really called for it.