Abstract:
This research applied cumulative plot and shockwave analysis to estimate queue length on arterial road in using five seconds interval traffic data collected from traffic detectors. Three detectors: at the downstream (A); at the middle of section (B); and at the upstream (C), were installed on the section. The queue estimation was carried out for both the traffic condition that the queue did not reach the mid-section detector (A-B), and the traffic condition that the queue grew beyond the mid-section (B-C). The observed queue in the field was brought to compare with estimated queue in both detector B spillover and non-spillover cases. The results found significant error of cumulative plot estimation from non-stop vehicles in section considered, lane change, and time lag. For shockwave analysis, without using flow-density curve had error from fluctuation of shockwave values in each five seconds, but using q-k curve was able to reduce it and gave less error. To summarize, shockwave analysis gave more reliable estimation than cumulative plot, and B-C estimation could help to estimate queue in traffic congestion period.