Which factor is NOT considered when determining pavement thickness?

When determining pavement thickness, multiple factors such as traffic load, soil support value, and economics are all taken into account. Traffic is crucial because the volume and type of vehicles that will be using the roadway directly influence the stresses that the pavement will experience. Soil support value is also essential as it indicates the strength of the underlying ground, which affects how well it can support the pavement structure. Economics can guide the decision-making process, balancing performance with cost-effectiveness.

Environmental impact, while a significant consideration for overall project planning and sustainability initiatives, does not directly influence the technical specifications of pavement thickness. It focuses more on the broader implications of the project rather than the engineering requirements needed for specific pavement design. Therefore, the correct choice identifies that environmental impact is not a determining factor for pavement thickness.