Enter the number of cumulative 18-kip equivalent single axel loads over the design life of the pavement structure and the lane distribution factor into the Traffic Index Calculator. The calculator will evaluate the Traffic Index.

## Traffic Index Formula

The following two example problems outline the steps and information needed to calculate the Traffic Index.

**TI = 9.0*(ESAL * LDF / 10^6) ^ .119**

Variables:

- TI is the Traffic Index ( )
- ESAL is the number of cumulative 18-kip equivalent single axel loads over the design life of the pavement structure
- LDF is the lane distribution factor

## How to Calculate Traffic Index?

The following steps outline how to calculate the Traffic Index.

- First, determine the number of cumulative 18-kip equivalent single axel loads over the design life of the pavement structure.
- Next, determine the lane distribution factor.
- Next, gather the formula from above = TI = 9.0*(ESAL * LDF / 10^6) ^ .119.
- Finally, calculate the Traffic Index.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

number of cumulative 18-kip equivalent single axel loads over the design life of the pavement structure = 35,000,000

lane distribution factor = .75

TI = 9.0*(ESAL * LDF / 10^6) ^ .119** **= ?