This article describes the MELYSSA weather related traffic management pilot project. The general objective is to monitor driving speed on a motorway in bad weather conditions, and to ascertain how this can be modified by speed limitations imposed using variable message signs (VMS). Brief details about the sensors used to both measure and anticipate poor weather conditions such as fog, wind, rain, ice, and dazzling sunlight are provided. The measurements required to anticipate traffic flows, such as the speed, density and headways are also presented briefly. The spacing of the variable message signs is given. Forecasts made by using the equipment are compared with those made by direct observation, so that the accuracy of the forecasts can be assessed. The impact of speed limits imposed via VMS upon driver's speed are also presented.
Abstract