Aerodynamic Effects on Two-Lane Rural Highway Safety

Abstract

Two-lane rural highways experience a higher rate of traffic accidents than to other types of highways. One factor affecting this rate is the impact of aerodynamics on a vehicle’s stability and safety during crossing and overtaking maneuvers, especially under adverse environmental conditions such as crosswinds. This study investigated this phenomenon by using three-dimensional, unsteady computation fluid dynamics (CFD) simulations, with validation from wind tunnel experiments. The forces and moments acting on the vehicles were analyzed, and experiments showed that the forces acting on a vehicle may increase by up to 9 times, with the maximum increase associated with a size discrepancy between the vehicles. The presence of crosswinds increased the variations in fluctuations of forces and moments. To evaluate existing highway policies, additional parametric studies are needed to fully investigate the impacts of different crosswind speeds and directions, as well as different lateral distances between vehicles during crossing and overtaking maneuvers.