Chapter 3: Traffic loading

Consideration of the cumulative traffic loading over the design life of a pavement is one of the most important parameters in the design of new pavements and the maintenance and rehabilitation design of existing structures. Loading is generally associated with the structural design of pavements and typically follows a process that

In engineering designs a factor of safety (FoS) is often used to express how much stronger a system is than it needs to be for an intended load. This is an understandable concept for the design of civil engineering infrastructure, where failure is unacceptable. For example, structural steelwork in a bridge may be designed to an FoS of between 5 and 7 and this ensures that designs are safe. Ensuring a structure, such as a bridge or building, has adequate strength through the use of an appropriate FoS is a logical approach to protect the safety of users. Pavement engineering is a relatively unique discipline of civil engineering in that engineers often design to a point where at the end of its life the pavement structure is at, or close to, failure. Trafficking a pavement up to, and sometimes beyond, failure condition is often considered good asset management (i.e. sweating the asset to achieve maximum serviceable life). This would be unimaginable for most civil engineering assets, where failure would endanger users.