Passenger car unit: - In order to convert the different vehicles classes to one class such as passenger car conversion factor, is known as passenger car unit.

Factors affecting passenger car unit:-

1) It depends upon the factors like environmental and climatic conditions.

2) It depends upon the factors like dimensions, power, speed, acceleration and braking characteristics.

3) It depends upon the factors like roadway characteristics which includes road geometrics, rural or urban roads and types of intersections.

4) It depends upon the factors like different vehicle classes.

5) It depends upon the factors like regulations and control of traffic.