Diagnosing Road Weather Conditions with Vehicle Probe Data Results from Detroit IntelliDrive Field Study

Over the past 2 years, the U.S. Department of Transportation RITA funded an IntelliDrive vehicle probe data collection test bed in the northwest Detroit, Michigan, area. The purpose of the test bed was to provide the infrastructure for both public and private organizations to collect, process, and generate a robust observation data set for multiple purposes (e.g., crash avoidance, automated toll services, weather diagnostics). During April 2009, a weather-specific field study was performed over an 11-day period. The resulting data set was processed by a vehicle data translator (VDT), which parsed, quality controlled, and combined these data (with ancillary weather data) in the generation of road weather-specific algorithms. This paper briefly describes the VDT concept and then examines the accuracy of the quality-controlled temperature and pressure data (for several different stratifications) collected from 11 specially equipped vehicles operated during the study time period. Results show that the vehicles accurately measure the temperature (compared with a nearby fixed weather station, KDTW), but are not as accurate at measuring the barometric pressure. In addition, stratification by speed, vehicle type, time of day, and occurrence of precipitation do not affect the accuracy of the temperature and barometric pressure measurements.