Jensen, Maureen

MnDOTs Rail Administration Section monitors the safety performance of more than 4,000 public rail grade crossings and develops the Departments Railroad-Highway Grade Crossing Safety Improvement Program. A total of 445 vehicle-train crashes occurred at the public crossings during the 10-year study period, extending from 2004 through 2013. Of these crashes, 52 involved fatalities and another 129 involved injuries. Analysis of the crash data reveals two key points; the density of fatal plus injury crashes is very low - 0.004 per grade crossing per year and almost 91 percent of the crossings had NO crashes of any kind during the study period. This data combined with the fact that Rail Administration staff used a pair of crash prediction models that included consideration of crash history (along with crossing geometry and train/vehicle exposure factors) to identify candidates for safety investment raised concern among MnDOT staff regarding whether or not the models placed too high a priority on prior crash history. This set of facts resulted in undertaking a study to determine how well the prediction models fit Minnesotas data and to attempt to identify a set of grade crossing risk factors that would support a statewide systemic evaluation. The study determined that both the FRA Accident Prediction Model and the Texas Hazard Index were poor fits with Minnesotas crash data. The study also identified a set of volume, speed, design and surrounding area features that were over-represented at crossings with crashes and that the crossings with multiples of these features present had the highest crash densities and could be considered high priority candidates for safety investment.

Highway agencies with an inventory of traffic signs must adopt a method of maintaining those signs so that the retroreflectivity exceeds established thresholds. Understanding expected sign life can help agencies phase sign replacements over a number of years in order to manage maintenance costs. The primary goal of this research is to provide objective data about sign life based on the degradation of retroreflectivity and color over time. A literature review found sign retroreflectivity research around the country, however, none of the studies are conclusive. Eight Minnesota agencies took retroreflectometer readings on in-place signs across the state. Disaggregated measurements by sheeting material and color did not leave a large enough sample for conclusive results, and very few signs fell below minimum retroreflectivity thresholds. Data suggests sign life exceeds the manufacturer's warranty and that a controlled environment with known conditions will produce more reliable data. MnDOT established a test deck at MnROAD to take multiple retroreflectivity and color readings over time to the point of failure in a controlled environment. The best information inferred from the results is an estimate for an expected sign life of 12 to 20 years for beaded sheeting and 15 to 30 years for prismatic sheeting. Agencies are encouraged to move forward and adopt a sign maintenance method and expected sign life by bringing sign management decisions under an umbrella of immunity. This document has suggested best policy practices and statements for sign maintenance and management assembled by a panel including engineers and risk management specialists.