LAUSR

The high proportion of motorcycles and lack of lane discipline at signalized intersections under mixed traffic conditions are the motivation to conduct this study. The discharge headway models are constructed at three (3) signalized intersections in the SARBAGITA urban area in Bali. The result shows that motorcycles affect saturation flow due to their shorter headway than light vehicles while increasing discharge headway of other vehicles. The discharge headway between pairs of heavy vehicles is longer than these of motorcycles due to their slower acceleration at signalized intersections. This study also found that the discharge headway plays a significant role in determining the saturation flow and capacity of a signalized intersection. If a heavy vehicle is one of the pairs, then it has the potential to have a headway exceeding the other vehicle pairs. This indicates, however, that the higher proportion of motorcycles at the signalized intersection approach does not necessarily mean shorter discharge headway. There may be other influencing factors, such as the riding behavior of motorcyclists. The dominance of motorcycles can affect the value of the saturated flow, but an increase in the proportion of heavy vehicles may reduce the effect of motorcycles on the saturation flows.