• An Empirical Model for Optimal Highway Durability in Cold Regions

      Yan, Jia (Center for Environmentally Sustainable Transportation in Cold Climates, 2016-03-10)
      We develop an empirical tool to estimate optimal highway durability in cold regions. To test the model, we assemble a data set containing all highway construction and maintenance projects in Arizona and Washington State from 1990 to 2014. The data set includes information on location, time, type (resurfacing, construction, or lane widening), pavement material and thickness, and total expenditure for these projects. Using the data, we first estimate how highway maintenance costs and highway duration depend on pavement thickness and traffic loading. We then calibrate the effects of different deicers on highway durability and thus on highway maintenance costs. Finally, we demonstrate how the estimated and calibrated model can be used by planners to make optimal decisions for highway pavement and winter operations in cold regions.
    • The Impact of Snowfall on Airport Operations and Delays

      Lee, Jukwan; Yan, Jia (2019-03-31)
      Flight delays or cancelations due to snowfall are a costly inconvenience, not only to airports but also to airlines, passengers and society as a whole. However, no quantitative research has ever been done to provide an analytical explanation about the issue. Though being a reliable alternative to melt snow on the runway and mitigate flight delays, the Heated Pavement System is not adopted in any US airports because of concerns over the initial investments and maintenance costs being higher than the economic loss from delays during unpredictable snowfall days. Combining weather and domestic flight data in Boston and Los Angeles regions, we analyze the benefits and costs associated with installing the Heated Pavement System. Using two advanced econometric methods, the Difference in Difference in Difference (DDD) and the nearest neighbor matching, we first develop a Delay Analysis model to evaluate the exact effect of snowfall on flight delays, and then we calculate the delay costs. Based on the empirical findings, we conduct cost-benefit analysis of installing HPS at the three airports in Boston area. Our results indicate that HPS is feasible for airports with a great number of flights and passengers, such as Boston Logan airport.