Classification of roads according to the HCM6 method and its application in Polish conditions

Abstract

Abstract The development of the road network and the increasing volume of traffic causes more problems with capacity and deteriorating traffic conditions. This may be a direct cause of making wrong decisions and actions to improve the road traffic flow on road sections. In order to eliminate the traffic congestion and improve the traffic flow, it is necessary to determine the traffic parameters, and based on them to indicate the capacity and a level of service. One of the most commonly used methods for estimating capacity and traffic conditions is the Highway Capacity Manual method. This methodology was developed in the United States and is based on the conditions and parameters of traffic occurring in this country. Authors in the paper indicate problems related to the use of this methodology in Polish conditions, based on the tests results obtained for the section of the national road. Differences between conditions in Poland and in the USA occur already at the stage of division of roads into groups. The proposition of the classification of all national roads to transit routes may cause significant analysis errors. The authors of the HCM method assume the occurrence of high speeds on transit roads and this parameter determines the level of service. In the case of some national roads in Poland, their route runs through built-up areas where administrative speed restrictions and additional restrictions are arranged to improve safety. Such a situation may cause an error at the beginning of the analysis, in determining the level of service. This may be a direct cause of making wrong decisions and actions to improve the road traffic flow on road sections. The lack of proper interpretation of the HCM method may cause significant errors in the analysis results. The authors in the article pay attention to the characteristic parameters of the road infrastructure, which may have a significant impact on these errors.