A Macroscopic Spatial Model Analysis of Traffic flow: A case study of Nyeri town

Abstract

Traffic flow analysis is an essential component of a town’s traffic and transport systems since these flows could, and often do, lead to the occurrence of congestion on our roads. Traffic congestion is a growing problem not only in Nyeri, but also in most major towns of Kenya, resulting from rapidly increasing population and the crowding of motorized traffic onto a limited street network. This objective of the research was to perform spatial analysis of traffic flows on the key road links in Nyeri town. On those selected road links the study also established fundamental traffic flow models and derived the flow characteristics associated with traffic operations in Nyeri town, determined the characteristics of a Macroscopic Fundamental Diagram (MFD) for Nyeri town and assessed whether it is a property of the network infrastructure and control or a property of the travel demand. In this research, MetroCount Vehicle Classifier was used to collect traffic flow intensity and velocity data at seven different locations of the network. The analysis of the data was performed by the MetroCount Traffic Executive MCReport and the desired variables/parameters; speed, volume and density; were compared and their relationships established. From this research, the MFD derived from the data serve as a road network performance indicator, which shows the performance levels of Nyeri town in terms of traffic flow. The research was used to determine the capacity of the road network and the level of congestion in different links thereby determining the adequacy of the network. It was found that the speeds in Nyeri town are moderate and that the volumes of traffic in Nyeri town are low. However, this should not have been case, since when the volume of a network is low; the speeds are expected to be high. From the research, it was found that a MFD exists for Nyeri town; however, it depicted the non-congestion phase of the “full” diagram. The results of this research will lead to better traffic management and improve mobility and accessibility in Nyeri town. Researches in land use components should be investigated to determine how they influence or explain some of the results of this research.