Splash and spray production from heavy trucks under wet weather conditions has been a concern for many years. The history of this area of research and development is described, in the context of Federal mandates in recent years. The laser transmissometer technology pioneered by Systems Technology Inc. has been further developed by the Texas Transportation Institute over the past four years. This methodology is described, and data reduction/analysis approaches are discussed, especially accounting for the influence of wind direction and velocity. General findings and recommendations for future R and D are provided for the two basic approaches to diminishing splash and spray from heavy trucks; redirection of water and aerodynamic treatment of the vehicle.
