UC Davis Institute of Transportation Studies

The intention of the study is to demonstrate the potential economic effects of delayed road maintenance and management, leading to deteriorated riding quality and subsequent increased vehicle operating costs, vehicle damage, and freight damage. The overall objectives of this project are to enable Caltrans to better manage the risks of decisions regarding freight and the management and preservation of the pavement network, as the potential effects of such decisions (i.e., to resurface and improve riding quality earlier or delay such a decision for a specific pavement) will be quantifiable in economic terms. This objective will be reached through applying the principles of vehicle-pavement interaction (V-PI) and state-of-the-practice tools to simulate and measure peak loads and vertical acceleration of trucks and their freight on a selected range of typical pavement surface profiles on the State Highway System (SHS) for a specific region or Caltrans district. The objectives of this report are to provide information on Tasks 9 to 11. Conclusions The following conclusions are drawn based on the information provided and discussed in this report:  Road roughness data can be used in conjunction with appropriate models and relationships to evaluate the economic effect of road use by logistics companies through evaluation of vehicle operating costs (VOCs) and potential damage to vehicles and freight.  As road roughness generally deteriorates with road use, road owners can evaluate the economic changes in the VOCs of road users over time, and determine optimum times for maintenance and rehabilitation of existing transportation infrastructure.  Road users can use relationships between road roughness and various parameters (VOCs, freight damage, etc.) to select optimal routes where VOCs and damage are minimized and also objectively calculate the effect of these road conditions on their income.  Road owners can evaluate the effect of different levels of construction and maintenance quality control on the outcome of these actions and the general transportation costs and deterioration rates of the infrastructure as affected by riding quality/road roughness. Recommendations The following recommendations are made based on the information provided and discussed in this report:  The models and relationships in the report should be evaluated for incorporation into the appropriate Caltrans economic models, to enable modeling of the effects of riding quality and deterioration of riding quality over time on economic models.  Analysis of the effect of construction and maintenance quality control using local maintenance options and their effects on the riding quality of roads should be evaluated to enable appropriate control levels to be determined.  The effects of riding quality bonus-penalty schemes, and the effect of initial riding quality on the long-term performance of local roads, should be incorporated into an overall transportation infrastructure model.  Further studies on the damage determination of transported agricultural produce at a range of frequencies caused by various riding quality truck combinations using laboratory-based bulk density measurements should be conducted (similar to the tomato tests discussed in this report).