Traffic-related pollutants adversely affect air quality

especially in regions near major roadways. The vehicleinduced turbulence (VIT) is a significant factor that controls the initial dilution

dispersion

and ultimately the chemical and physical fate of pollutants by altering the conditions in the microenvironment. This study used a computational fluid dynamics (CFD) software FLUENT to model the vehicle-induced turbulence (VIT) generated on roadways

with a focus on impact of vehicle-vehicle interactions

traffic density and vehicle composition on turbulent kinetic energy (TKE). We show

for the first time

that the overall TKE from multiple vehicles traveling in series can be estimated by superimposing the TKE of each vehicle

without considering the distance between themwhile the distance is greater than one vehicle length. This finding is particularly significant since it enables a new approach to VIT simulations where the overall TKE is calculated as a function of number of vehicles. We found that the interactions between vehicles traveling next to each other in adjacent lanes are insignificant

regardless the directions of the traffic flow. Consequently

simulations of different traffic scenarios can be substantially simplified by treating two-way traffic as one-way traffic

with less than 5% difference in the overall volume-averaged TKE. We also developed equations that allow the estimation of the overall volume-averaged TKE as a function of the number and the type of vehicles.