greater than 0.5. An example would be an industry where material is hauled in by truck
and shipped out by rail. In this case, loaded trucks would be going into the plant and empty
trucks would be exiting the plant. The next factor is the lane distribution factor. As more
lanes are added to a section of road, the traffic will be more distributed among these lanes.
However, trucks tend to use the outermost lane, so the distribution of ESALs is not in
proportion to the number of lanes added. Many of the state DOTs have developed lane
distribution factors for use in pavement design. The AASHTO Pavement Design
Guide presents a range of factors used for lane distribution as given below. It should
be noted that for the same traffic, the thickness design will be greater for the pavement
with the smaller number of lanes.