Impact of Variable Speed Limit in a Connected Vehicle Environment on Truck Driver Behavior under Adverse Weather Conditions: Driving Simulator Study

Abstract

In 2015, the U.S. Department of Transportation (U.S. DOT) selected Wyoming as one of three sites to develop, test, and deploy a suite of connected vehicle (CV) applications on a 402-mi Interstate 80 corridor. One of the Wyoming’s key CV applications is the variable speed limit (VSL) warning, which aimed to provide commercial truck drivers with real-time regulatory and advisory speed limits to help in better managing speeds under adverse weather conditions, and reducing potential speed variances that may cause traffic collisions. This paper developed a driving simulator testbed to assess the impact of the Wyoming’s CV-based VSL (CV-VSL) application on truck drivers’ behavior under adverse weather conditions. A total of 18 professional truck drivers were recruited to participate in the driving simulator experiment. Participants’ instantaneous speeds at various locations were collected to reveal the impact of the CV-VSL warnings on their driving behavior. Simulation results showed that when the advisory speed limits were lower than 55 mph, participants generally followed the VSLs displayed on the CV human–machine interface (HMI). In addition, traffic flows utilizing CV-VSL technology tend to exhibit lower average speeds and speed variances compared with baseline scenarios. These effects of CV-VSL warnings can bring potential safety benefits, as reduction in average speeds and speed variances are effective surrogate measures of safety, that is, lower risk of crashes, under adverse weather conditions.

Intention of Risk-Taking Behavior at Unsignalized Intersections Under the Connected Vehicle Environment

“…Compared with the non-CV environment, drivers under the CV environment have a higher value of attitudes to accelerate through the unsignalized intersection, which means drivers under the CV environment held a more negative attitude to accelerate the unsignalized intersection than those under the non-CV environment. This finding is in line with Yang, et al [56], who indicated that real-time information could significantly affect driver attitudes under the CV environment. Also, drivers under the CV environment have a lower risk perception than drivers under the non-CV environment if they accelerate through the unsignalized intersection.…”

Performance evaluation framework of Wyoming connected vehicle pilot deployment program: summary of Phase 2 pre-deployment efforts and lessons learned

“…Currently, the University of Wyoming research team conducted a driving simulator study to provide early insights about the impacts of CV warnings on driver behavior (Raddaoui et al, 2019;Yang et al, 2019). It was concluded that both average and variance of speed under CV scenarios were significantly lower than baseline scenario.…”

“…The driver behavior data mainly include car-following headway, standstill distance, minimum front to rear headway, lane-changing gap, acceleration and deceleration rates, waiting time before diffusion, etc. In addition to collect naturalistic driver behavior data under adverse weather conditions and/or in a CV environment, an alternative method for calibrating CV microsimulation models is using driver behavior data generated from high-fidelity driving simulators (Chen et al, 2019;Yang et al, 2019), which can overcome the limitation of the field data-based model calibration approach.…”

Connected Vehicle Training Framework and Lessons Learned to Improve Safety of Highway Patrol Troopers

“…Several studies have shown the significant benefits of CV technology in enhancing the traffic safety of drivers (28)(29)(30)(31)(32)(33)(34). A study showed that traffic safety could be increased by providing the appropriate driving speed using CV technology (35). Providing the appropriate driving speed for the encountered conditions would lower the speed variation.…”