DRIVER BEHAVIOR DURING LANE CHANGE FROM THE 100 - CAR NATURALISTIC DRIVING STUDY Rong

Lane changes with the intention to overtake the vehicle in front are especially challenging scenarios for forward collision warning (FCW) designs. These overtaking maneuvers can occur at high relative vehicle speeds and often involve no brake and/or turn signal application. Therefore, overtaking presents the potential of erroneously triggering the FCW. A better understanding of lane change events can improve designs of human-machine interface and increase driver acceptance of FCW. The objective of this study was to characterize driver behavior during lane change events using naturalistic driving data. The analysis was based on data from the 100-Car naturalistic driving study, collected by the Virginia Tech Transportation Institute. The 100-Car study contains approximately 1.2 million vehicle miles of driving and 43,000 hours of data collected from 108 primary drivers. In order to identify overtaking maneuvers from a large sample of driving data, our study developed and validated an algorithm to automatically identify overtaking events. The lead vehicle and minimum time to collision (TTC) at the start of lane change events was identified using radar processing techniques developed in a previous study. The lane change identification algorithm was validated against video analysis which manually identified 1,425 lane change events from approximately 126 full trips. Forty-five (45) drivers with valid time series data was selected from the 100-Car study. From the sample of drivers, our algorithm identified 326,238 lane change events. Lane change events were evenly distributed between left side and right side lane change. The characterization of lane change frequency and minimum TTC was divided into 10 mph speed bins for vehicle travel speeds between 10 mph to 90 mph. A total of 90,639 lane change events were found to involve a closing lead vehicle. For all lane change events with a closing lead vehicle, the results showed that drivers change lanes most frequently in the 50-60 mph speed range. Minimum TTC was found to increase with travel speed, and the variability in minimum TTC between drivers also increased with travel speed.