Tons for a rough and ready answer, kilograms for a more accurate answer.
meters
The answer depends on what you wish to measure: its length (or width or height), its mass, it fuel efficiency, it maximum speed, its maximum acceleration, its tightest turning circle, its power output, its drag, etc.
You can use either unit of measurement.
Probably kilometers or miles :)
Meters
what is the most suitable unit to measure the length of a car key
That is optional. The best unit of measurment would probably be tons.By:Donny Heitler
mass
It is customary to use the kilogram - though that is technically not a weight, but a mass.
The best metric unit to measure how much a car weighs is kilograms (kg). This unit is commonly used for measuring weights of objects, including vehicles like cars, and provides a simple and easy-to-understand measurement of mass.
It is a kilonewton.
Tons for a rough and ready answer, kilograms for a more accurate answer.
feet The meter (m) is the international unit (in SI) for length.
a tape measure of at least 25 feet or more
meters
A kilogram