What is the customary unit to the length of a car

The customary unit to the length of a car is meter. This is one of the units of the International System (SI). The international units are standards that permit to compare measures made in different places by different persons. Any one will be able to compare the length of a car is you say that it is 3.5 meters long or 5.2 meters long, no matter if that person is in USA or in China. The use of international standards was promoted by the scientific communities as a way to make it possible a better understanding and development of scientific work.