Freeway performance measures are extracted from Traffic Monitoring Stations which gather traffic volume and speed data. Reported freeway speeds areusually aggregated over a period of 20 or 30-second or 1, 5, or 15-minuteby traffic agencies. This paper evaluates how various aggregation intervals impact accuracy and reliability of the reported freeway loop detector speeds and determines the optimal aggregation interval. The study compares speeds collected by probe vehicles equipped with Global Positioning Systemversus aggregated detector speeds. Results indicate the need to archive 20-second detector data in addition to current 15-minute data archiving by the Utah Department of Transportation.
Samenvatting