The Maintenance Decision Support System (MDSS) is a decision support tool that integrates relevant road weather forecasts, coded maintenance rules of practice, and maintenance resource data to provide winter maintenance managers with recommended road treatment strategies. Sixteen states have joined the MDSS Pooled Fund Study led by the South Dakota DOT to develop an enhanced version based on the federal MDSS prototype.
The purpose of this research project was to assess the benefits and costs associated with implementation of MDSS by state transportation agencies.
Three states, New Hampshire, Minnesota, and Colorado, were chosen to provide case studies on the benefit-cost ratio of using MDSS. The three states were selected because they:
- Represented different climates
- Provided good historical data on maintenance problems
- Captured a variety of traffic and terrain conditions
Several years of historic weather, maintenance, and traffic use data were incorporated to establish baseline information for each route segment. Then, a simulation generated output from the MDSS for each of three scenarios: base case (point 1), same resources (Point 2), and same conditions (Point 3). The simulation outputs from selected route segments were extrapolated to other route segments in the state to achieve a statewide benefit-cost analysis.
Figure 1: Benefit-Cost Methodology
Point 1 = Base Case
Point 2 = Keep Resources the same (better level of service)
Point 3 = Keep Level of Service the same (fewer resources)
The case studies showed that the annual net benefits of using MDSS outweighed the costs, by significant amounts, ranging from $2.68 million to $488,000. The benefit-cost findings are shown in the table below. The benefit-cost ratios do not indicate conclusively which scenario produces better results. The case studies showed that there is a trade-off between agency benefits and user benefits. Increased use of material will achieve more motorist benefits while increasing agency costs, and vice versa.
Table 1: Benefit-Cost Summary
User Savings (%)
Agency Savings (%)
From investigation of the benefits of the "Same Condition" scenario and material costs, the study authors found that the ratios of benefits over materials costs are 0.31, 0.36, and 0.30 for the three case studies. A state DOT may calculate the benefits by using the conservative 0.30 multiple of material costs per winter season to estimate benefits under the "Same Condition" scenario. It is noted that under this scenario, approximately half of the benefits accrue to the agency and half accrue to the motorist.