Effectiveness of Various Ways of Providing Access and Service of Road Surroundings on Suburban Roads

The process of urban deglomeration, in which part of city populations migrate out of the city into the suburbs, has, over the last ten years led to strong growth of the suburbs. This has resulted in the construction of commercial and residential buildings alongside sections of national roads carrying traffic in and out of city. In most cases this development has direct access to the major road. The construction of residential buildings as well as commercial buildings in the immediate vicinity of major roads, without building service and local roads network is a frequent phenomenon in Central and Eastern Europe. Driveways to buildings are densely packed along such roads and can reach as many as 80 per kilometre, although the traffic during the day is very low. The traffic peak is in the morning peak when the flow of traffic into town is the heaviest. It causes overlapping of commuter and through traffic and leads to interruptions of traffic flow and deterioration of traffic conditions. Journey speed is reduced and greater delays extend journey times through urban areas. This phenomenon can be encountered not only in suburban areas, where it has the most adverse consequences, but also on those sections of roads that pass traffic through localities. The authors‟ research indicates that in Poland, some 35% of major roads length go through small communities. This state results from planning errors and poor regulations of land-use policy. Lack of adequate policies has degraded the parts of road network which have basic traffic function. This situation is further compounded by lack of network of express roads and motorways and inadequate development of road network transformation including construction of by-passes. One radical change would involve a hierarchical road network, though it is a costly and long-term challenge. Following the arguments above, the authors undertook research. Their aim was to find out about the possibility of using less costly modifications of road networks and changes in the service of road surroundings to ensure an improvement in the conditions of through traffic in suburban areas and on roads passing through smaller localities. The issues concern sections of roads with a two-lane cross-section. From among possible designs, the authors have chosen to investigate and present in the study the effectiveness of the following designs: Implementing an additional multifunctional median lane, specially signed and marked (also red surface) in the road cross-section; and Construction of service roads with different locations of intersections merging traffic with the existing road (end or middle of a section). The analysis focused on the impact of such changes on traffic efficiency and safety. The authors analysed journey speed, delay and platoon traffic on a uniform section of the road for different modes of service of road surroundings. Furthermore, the study presents the results of analyses covering the evaluations of: impact of access points density and level of their use on road traffic conditions; impact of driving through sections in built-up area on building platoon traffic; and impact of change in the cross-section type on traffic conditions.