An Ensemble Strategy For Road Weather Applications

Abstract

In 1999 the Federal Highways Administration (FHWA) initiated a 5-year program to explore the applicability of technologies developed at national research laboratories to the problem of winter road maintenance. The first specific goal was to develop an automated decision support system to generate snow plowing and pavement chemical application guidance for use by state departments of transportation. The project, and the system, were named the Maintenance Decision Support System (Mahoney and Myers 2003). A block diagram of MDSS is shown in Figure 1. The gridded outputs from an ensemble of mesoscale model forecasts generated by the NOAA Forecast Systems Laboratory (FSL) are transmitted in real time to the National Center for Atmospheric Research’s Research Applications Laboratory. There, the FSL models are ingested along with the models produced by the National Weather Service’s National Center for Environmental Prediction (NCEP), namely the Eta and Aviation (AVN) models, into the Road Weather Forecast System (RWFS). RWFS uses dynamic model output statistics (DMOS) techniques to optimize forecasts of temperature, wind, humidity, insolation, and precipitation for several dozen prediction points along targeted roadways. Most of these prediction points correspond to the locations of Road Weather Information Systems (RWIS) of automated sensors that provide verification for the RWFS forecasts. The point forecasts generated by RWFS are used to inform pavement temperature and chemical concentration modules developed by the Cold Regions Research and Engineering Laboratory (CRREL). The pavement condition predictions are used with encoded rules of practice, developed by the Massachusetts Institute of Technology Lincoln Laboratories (MIT/LL), to suggest plowing and chemical applications strategies (e.g., “plow Highway 10 three times between midnight and 6 AM and spread 150 lbs of salt per lane mile”). Finally, the weather and guidance information is transmitted to a graphical user interface running on personal computers in the offices of snowplow garage supervisors.