This document presents key findings from the light-vehicle field operational test conducted as part of the Integrated Vehicle-Based Safety Systems program. These findings are the result of analyses performed by the University of Michigan Transportation Research Institute to examine the effects of a prototype integrated crash warning system on driving behavior and driver acceptance. The light-vehicle platform included four integrated crash-warning subsystems (forward-crash, lateral-drift, lane-change/merge crash, and curve-speed warnings) installed on a fleet of 16 passenger cars and operated by 108 randomlysampled drivers for a period of six weeks each. Each car was instrumented to capture detailed data on the driving environment, driver behavior, warning system activity, and vehicle kinematics. Data on driver acceptance was collected through a post-drive survey, debriefings and focus groups. Key findings indicate that use of the integrated crash warning system resulted in improvements in lanekeeping, fewer lane departures, and increased turn-signal use. The research also indicated that drivers were slightly more likely to maintain shorter headways with the integrated system. No negative behavioral adaptation effects were observed as a result of drivers' involvement in secondary task behaviors. Drivers generally accepted the integrated crash warning system and 72 percent of all drivers said they would like to have an integrated warning system in their personal vehicles. Drivers also reported that they found the blind-spot detection component of the lane-change/merge crash warning system to be the most useful and satisfying aspect of the integrated system.

One hundred eight drivers participated in a naturalistic field operational test. Each participant drove an instrumented passenger car for 6 weeks. Video data from the first week of driving for each participant were visually scored for all instances of cell phone use. These instances were divided into cell phone calls (conversations) and cell phone interactions that were not calls (visual or manual tasks involving the cell phone). Researchers examined 1,382 conversations and 2,149 visual or manual tasks. Participants were engaged in cell phone conversations 6.7% of all driving time and in visual or manual tasks involving a cell phone 2.3% of all driving time. Overall, conversations had a mean duration of 2.6 min, and participants engaged in conversations at a rate of 1.5 conversations per hour. Younger drivers were significantly more likely to be engaged in either type of cell phone task than older drivers and significantly more likely to be engaged in visual or manual tasks than middle-aged drivers. Drivers were more likely to initiate conversations and visual or manual tasks when stopped than at higher speeds; this finding may suggest a level of self-regulation. Furthermore, the finding suggests that estimates of crash risk that are based on assumptions that behavior observed in stopped vehicles translates to behavior in moving vehicles is incorrect and will result in overestimates of driver engagement in cell phone use.

No abstract