Analyse fine des trafics lourds

The characteristics of in-service heavy vehicles have been recorded over three highly contrasting road types, an urban, an interurban and an international one. The traffic of all commercial vehicles weighing at least 2 tonnes has been studied over a full week, so that for all three sites, about 20 000 commercial vehicles have been fully described. Two different methods have been used to record the various variables: a survey among drivers on the international road, using the vehicle stop at the Mont Blanc tunnel toll (several interviewers, stationed simultaneously by each toll lane, took turns, both night and day, noting all information required; an automatic monitoring station located on one of the main thoroughfares of Lyons as the urban site, and on a highway near Chambéry (Savoy) as the intercity road. The station selected vehicles over 2 tonnes and operated in-motion weighing (with cables embedded in the road surface) and video recording (with a camera pointed at traffic). The video tapes were subsequently examined. Proposed statistics are of two kinds: an analysis of the heavy traffic for each road type (percentage of heavy vehicles in the global traffic, daily levels, week evolution, day/night discrepancies and composition in four vehicle types); a comparative study of the variables characterizing these four groups of vehicles (vans, solo lorries, long lorries (semitrailers and road trains) and buses). These variables are: type, axle number, horsepower, overall weight, speed over a short route, presence of a refrigeration unit, and length and nationality in the intercity and international cases. All the variables form a unique database about in-service commercial vehicles. This database will provide input data for models of polluting emissions from this traffic.