Roadway & Roadside Maintenance

Summary:

Effective winter road maintenance is crucial for safe travel and represents a substantial portion of the Michigan Department of Transportation’s (MDOT) annual budget. A primary challenge in winter operations is resource allocation for different winter maintenance materials, due to the substantial variability in winter weather conditions across Michigan’s diverse regions. MDOT currently employs a Weather Severity Index (WSI); however, this existing WSI does not explicitly account for regional differences in weather phenomena or directly translate weather severity into associated maintenance costs. To address this challenge, this study aimed to develop a more accurate and actionable index linking regional weather conditions directly to winter maintenance costs. Initially, a comprehensive literature review was conducted to identify best practices nationwide. This review revealed a variety of approaches among state Departments of Transportation agencies, emphasizing the benefits of region-specific weather indices that directly correlate to maintenance expenditures. To gain further insights, two targeted surveys were conducted. First, a statewide survey of Michigan’s MDOT garages highlighted significant variability in local maintenance practices, driven primarily by localized weather phenomena such as lake-effect snow. Second, a nationwide DOT survey provided a broader perspective, confirming the value of integrating short-term forecasting and detailed weather data into severity indices to improve proactive resource management. Leveraging these insights, the research team developed the Material Cost-based Winter Severity Index (MC-WSI), explicitly designed to capture unique Michigan regional climates. The NOAA Climate Divisions were adopted as the regional framework, segmenting Michigan into 10 climatologically homogeneous regions. Due to limitations in operational cost data, standardized material unit costs derived from historical bid records were applied consistently across the state. Statistical analyses based on various weather factors correlated with material costs identified pavement temperature, hours of snowfall, and hours of freezing rain as the most significant predictors of monthly material usage. Robust linear regression models were developed and validated using five-fold cross-validation, confirming the high accuracy and reliability of the models. The MC-WSI depicts these predicted material costs into a standardized index ranging from 0 to 100, allowing decision-makers to directly interpret weather impacts and proactively adjust operational plans and budgets. Comparative assessments showed that the MC-WSI substantially outperforms the MDOT current index in correlating with actual material usage rates in different regions. Finally, strategic recommendations and future research opportunities were identified, including the adoption of MC-WSI into operational practice and developing an online tool for automated estimation and a short-term forecasting module integrated with an improved real-time data management system (weather features and maintenance costs). While specifically developed for Michigan, this research provides valuable methods and insights applicable to other states confronting similar winter maintenance challenges.  

 

Publications:

• Final Report
• Spotlight