Ingenieur Vol. 74 Ingenieur Vol 72, April-June 2018 - Page 48

INGENIEUR RESULTS AND DISCUSSION Input Data (Intersection, Approaches and Lanes) In SIDRA Intersection data can be entered using graphics-based input dialogues. The intersection geometry and signal phasing style of SIDRA Intersection directly reflects the design process. The approaches and lanes input dialogue allows the analyst to type in approach road names and specify the various data which describes the basic characteristic of an approach road (or intersection leg), and existing lanes. Then, movement class and lane declines are updated before the volume of vehicles is keyed in and the data is processed (refer to Figure 4.1). Existing condition (Before improvement) Level of service The value of delay, queue journey time and speed obtained from practical measuring data at the site shows the level of service (LOS). In the case study the LOS level is F and drivers experience long delays, long travel times and low speed. Figure 4.2 shows the existing LOS at the Bukit Chedang T-Junction. The current situation needs to be improved significantly in order to reduce the volume of traffic as well as effectively control traffic at the intersections. Results (After improvement) The results from the study show that the level of service requires improvement as well and the percentage dissimilarity before and after improvement can be observed. Figure 4.3 shows LOS change after improvements. After making some improvements in traffic light timing phase there was no significant improvement. Adjusting cycle time of the intersection according to the volume of traffic flow showed no significant improvement. The solution to significantly improve LOS at the junctions was changes in road alignment, with the addition of a slip lane to reduce the volume of congestion and long queues, and adding new lanes to increase the capacity of intersection. After an improvement/upgrading the results are shown in Figure 4.3. Figure 4.1: Lane Description and updated vehicle volumes 6 46 VOL 2018 VOL 74 55 APRIL-JUNE JUNE 2013