The Promotion of Resource Allocation Process in 3R Projects

In 2003, a process was developed in NCHRP Report 486 by TRB for allocating resources in Resurfacing, Restoration and Rehabilitation (3R) Projects after which the software called RSRAP was developed to execute such a process. In the said report, a set of impacts encountered after improving a network of road segments as 3R activities, and tradeoffs between them were introduced and quantified as the economic costs and benefits of the project, including:• CC: Construction Costs,• PSB: Present value of Safety Benefits,• PNR: Penalty for Not Resurfacing,• PRP: Present value of Resurfacing safety Penalty, and• PTOB: Present value of Traffic-Operational Benefits. All these costs and benefits were incorporated in a Cost-Benefit Analysis as an economic evaluation method and in an optimization process using Integer Programming Model, in order to find the best alternative in each site of the network. The ten-step process to fulfill the analysis and optimization purpose contains the following components [changes and promotions implemented in this study, are described in brackets]:• Identify the sites to be considered [no changes],• Identify the improvement alternatives (and combinations of alternatives) to be considered for each site [crest vertical curves, narrow bridges and Permanent Raised Pavement Markers (PRPMs) are added to geometric features],• Convert future costs and benefits to present values [discount rate are estimated for Iran],• Estimate the construction cost of each improvement alternative [unit construction costs are estimated for Iran],• Estimate the safety benefits for each improvement alternative [Accident Modification Factors (AMFs) are estimated and/or are considered for crest vertical curves, narrow bridges and Permanent Raised Pavement Markers; meanwhile, accident costs are also estimated for each Fatal, Injury and PDO accident severity level in Iran],• Estimate the penalty for not resurfacing [no changes],• Estimate the safety penalty for each improvement alternative that involves resurfacing without other geometric improvements [no changes],• Estimate the traffic-operational benefits for each improvement alternative [a new definition of vehicle speed increases is presented and is considered in quantified measure of PTOB; meanwhile, hourly time value is also estimated for each Iranian traveler.],• Determine the net benefits for each improvement alternative [new measures of costs and benefits are used for determining the net benefits], and• Select the most suitable improvement alternative for each site within the available budget by applying optimization logic [no changes in the model structure but the net benefit for each measure is estimated]. In this paper, by introducing the process mentioned above, some correcting measures are proposed to expand the procedure and redraw a more comprehensive perspective due to the future economic status of the 3R projects. The two substantial modifications illustrated in this paper are:1. Estimating and/or considering Accident Modification Factors (AMFs) for crest vertical curves, narrow bridges and Permanent Raised Pavement Markers (PRPMs) to expand the measure of PSB.2. Estimating the impact of improvements in geometric features on vehicle speed increase, beside the 1 mph increase mentioned in the previous research due to resurfacing improvements, and accommodating the total increase in estimation of the PTOB benefit. In addition, referring to the scopes of this research and as a further expansion in the resource allocation process of 3R projects, a wider range of the other impacts rising from such projects are evaluated. The four components which are added to the existing process are:• Assessing the real vehicle speed increases both due to geometric and resurfacing improvements (DS).