Assessing the performance of merge areas within the Maltese road network

Abstract

The merge area defines a crucial junction within the road network allowing the interaction of multiple traffic flows. Consequently, the merge area must accommodate the conflicting traffic demands while ensuring safety and preserving the operational integrity of the mainline carriageway. The fulfilment of such requirements relies mostly on the execution of the merge course. A successful merge course should encourage a constant path for the secondary traffic flow to join the mainline traffic flow with minimal interruptions. However, a number of considerations must be factored in the design process to accommodate a successful merge, which can be summed up into three main variables: (1) geometrical and physical characteristics of the merge area, (2) vehicle performance and (3) driver behaviour. The provision of merge facilities is pertinent to the Maltese road network, due to the dense built up area adjacent to the arterial road network intended to carry large traffic volumes at high speeds. Subsequently, the study aims to appraise the performance of a sample of merge areas within the Maltese road network to assimilate the local scenario. The research method consisted of an extensive field study, structured on the basis of a vast repertoire of literature, to extract primary data on-site and from video footage techniques. The data collected was processed to address four measures of efficiency including: the context of the merge area, geometrical and physical characteristics, division of merge location and speed difference. The deductions according to the four measures of efficiency inferred conflicting results to the interpretation of performance. The merge may abide to appropriate geometrical arrangements provided by the standards, however the relationship of secondary and mainline traffic flow has the major influence on the overall performance. Finally, the interpretation of results also dispute the relevance of the current standards applied to the Maltese road network and discusses potential alteration to the design process.