This document presents results from the light-vehicle and heavy-truck field operational tests performed as part of the Integrated Vehicle-Based Safety Systems (IVBSS) program. The 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 driver behavior and driver acceptance. Both platforms included three integrated crash-warning subsystems: forward crash; lateral drift; and lane-change/merge crash warnings. The light-vehicle platform also included curve-speed warning.
The IVBSS were introduced into two vehicle fleets: 16 light vehicles and 10 Class 8 tractors. The light vehicles were operated by 108 volunteer drivers for 6 weeks, and the heavy trucks were driven by 18 commercial-truck drivers for a 10-month period. Each vehicle 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 post-drive surveys and debriefings.
Key findings indicate that use of the IVBSS resulted in improvements in lane-keeping, fewer lane departures, and increased turn-signal use. No negative behavioral-adaptation effects of using the integrated system were observed in either driver group.
- For light vehicles, the integrated system had a statistically significant effect on the frequency of lane departures, decreasing the rate from 14.6 departures per 100 miles during baseline driving to 7.6 departures per 100 miles during the treatment condition.
- For heavy trucks, the integrated crash warning system had no effect on lane departure frequency, but a trend toward a decrease in lane departures was observed for 13 of the 18 drivers.
- A majority of drivers reported that their driving behavior changed as a result of using the integrated system. The most frequently mentioned change was an increase in turn-signal use, which was the result of receiving lane departure warnings triggered when drivers made unsignaled lane changes.