The curb weight, also known as the tare weight, of a car is the total weight of the car once it is manufactured. The curb weight contrasts with the gross vehicular weight, which is the curb weight of the car plus its passengers and cargo.
It is important to bear the gross vehicular weight in mind when driving a car. Going above the recommended gross vehicular weight causes the car to ride too low to the ground. It also decreases fuel efficiency; the engine has to work harder to haul a heavier car.
Consistently overloading a car also shortens engine life, because the engine and the other parts of the car have to work harder to haul a heavier load.