Survey data collected from tractor trailer drivers with one to three years of experience driving with intelligent vehicle safety systems (IVSS) indicate that IVSS lowers their perceived workload by 14 to 21 percent over a range of driving conditions.
Date Posted
09/23/2008
Identifier
2008-B00583
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Phase II Driver Survey Report: Volvo Intelligent Vehicle Initiative Field Operational Test: Final Report

Summary Information

The United States Department of Transportation (USDOT) entered into a cooperative agreement on September 29, 1999 with Volvo Trucks North America, Inc., in partnership with U.S. Xpress, to test and evaluate a radar-based collision warning system (CWS), an adaptive cruise control (ACC) system, and an advanced electronic braking system. The primary evaluation goal of the Field Operational Test was to determine the potential safety benefits of advanced Intelligent Vehicle Safety Systems (IVSS). Specifically, how many crashes, injuries, and fatalities could be avoided if vehicles were equipped with these technologies? It is also important to understand how these technologies affect driver performance. For example, do drivers drive more safely? And, how do these technologies affect driver stress level and workload?

The three safety systems under evaluation were developed to reduce the occurrence and severity of rear-end crashes as well as lane change/merge crashes. The radar-based CWS provides a forward sensor and a side sensor. The forward sensor sends a radar beam out from the front bumper to measure the following distance between the host (or subject) vehicle and the lead (or target) vehicle while the side sensor sends a radar beam into the right side blind spot of the tractor to check for vehicles that enter the driver’s blind spot on the right side of the truck. The ACC system maintains a fixed distance, dependent on road speed, between the host vehicle and the target vehicle ahead. When there is no detected vehicle ahead, the adaptive cruise control system maintains a given pre-set speed similar to conventional cruise control. The advanced electronic braking system, which includes air disc brakes and Electronically Controlled Braking Systems, was designed to enhance the tractor’s braking capabilities.

RESULTS

This report presents findings from an analysis of the data collected through driver surveys conducted at both the beginning and the end of the evaluation period. The first survey (Phase I) focused on driver expectations for the new safety technologies installed on selected Volvo trucks and the second survey (Phase II) focused on driver experiences using the technologies.

Survey data collected from tractor trailer drivers with one to three years of experience driving with intelligent vehicle safety systems (IVSS) —including radar-based collision warning systems (CWS), ACC systems, and advanced electronic braking systems—indicate that IVSS lowers their perceived workload by 14 to 21 percent over a range of driving conditions (good conditions, heavy traffic, and low visibility).