Determination of design traffic

The design traffic is the commercial vehicle loading over the design period expressed as the number of equivalent standard (80 kN) axles (ESAjo-icn)- The design traffic is calculated using the commercial vehicle flow, vehicle wear factors and traffic growth. 

A commercial vehicle (cv) is defined as that having a gross weight of more than 3.5 tonnes. Lighter vehicles are not taken into consideration since the structural wear caused is considered negligible. 

Commercial vehicles are classified into eight classes and three categories, as shown in Table 13.4. 

The pavement structural wear caused by a class of commercial vehicle is expressed by its wear factor (W). For the determination of the structural wear factor, the fourth power law was used to equate the wear caused by each vehicle type to the number of equivalent standard axles. A standard axle was defined as an axle applying a force of 80 kN. 

The methodology proposes different wear factors to be used for the pavement maintenance (W ) and new pavement design (Wj ) cases. These factors are given in Table 13.4. 

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