Prediction of Salt on Road Surface

Abstract

The competing goals of safety, accessibility, and environmental protection, together with limited funding, increase the need for cost-effective use of resources in the pursuit of winter maintenance activities. One way to minimize the amount of salt used in winter maintenance is to predict better the amount of residual salt on a road surface. This paper combines an empirical model developed in Sweden with data on residual salt, road surface wetness, and traffic from 18 Danish field case studies. The resulting model is presented as a mathematical function and in a graph. Decision makers might use such a model as a tool for understanding the durability of a dose of salt under various conditions (e.g., traffic, road surface wetness) and therefore minimize the amount of salt needed. The results of this study showed that the decay of residual salt could be modeled with traffic as an independent variable with a fair to quite good fit. Road surface wetness, as shown from the wheel tracks, related positively to the rate of residual salt loss. The wetter the surface, the faster the salt left the wheel tracks. On a wet road surface, the salt in the wheel tracks was almost gone after only a couple of hundred vehicles had traveled across the surface, whereas on a moist road surface, it would take a couple of thousand vehicles to reach the same result.