An Analysis of Unsignalised Intersection Using aaSIDRA Software

This thesis discusses about the use of Akcelik & Associates Signalised & Unsignalised Intersection Design and Research Aid (aaSIDRA Intersection) Software in the analysis of unsignalised intersection in Sarawak, Malaysia. aaSIDRA Intersection software was used to analyse the data which were manually obtained through traffic volume study carried out at the two junctions during the morning peak period and also helps in producing the capacity and Level of Service of the intersection. Four parameters were analysed in this thesis: critical gap, follow-up time, proportion of heavy vehicles or motorcycles and total number of vehicles for each of the approaches of the intersection. Referring to the Highway Capacity Manual (HCM), these variable parameter values are determined and then the expected output of the aaSidra being used in the analysis of this study are average control delay, existing level of service, and capacity of the junction. Fixed values to be input into SIDRA Intersection are obtained from the traffic volume study. The input influences the value for the average control delay which assists in determining the Level of Service of the intersection. These output values are highly influenced by the respective input values. All factors analysed under four parameters to determine the level of service of the two junctions were contributing equally and correlates with each other and there was not one that exceeds the other factor. The critical factors affecting the level of service are critical gap and traffic volume.