SPR-812

Description:

Pavement smoothness affects the lifespan of Arizona’s state highway network, the frequency of roadway maintenance and preservation projects needed to maintain it, and the cost to individuals of operating vehicles on it. Quantifying the impact of pavement smoothness specifications on pavement service life, vehicle operating costs, and emissions will help Arizona Department of Transportation (ADOT) determine appropriate smoothness standards for roadway construction and rehabilitation. For instance, pavements with a lower score on the International Roughness Index (IRI) typically require less maintenance and have a longer service life. Pavements with high IRI values can lead to increased overall vehicle maintenance costs for motorists, as rough roads cause tires and suspension systems to deteriorate at a faster rate and vehicles to consume more fuel. This study will estimate how changes to ADOT’s pavement surface smoothness specifications might extend pavement service life, delay the emergence of maintenance and rehabilitation (M&R) treatment triggers, and reduce vehicle operating costs for individual users. ADOT may use the findings of this study to modify smoothness specifications, producing statewide cost savings due to the increases in service life of pavements and reduced or deferred M&R activities. The results of this study may also be used to update project cost estimates and estimate user-cost savings.

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