Almost all motorcycles in Taiwan are less than 250cc in engine displacement. They are small-size motorcycles. Since their operational characteristics are quite different from automobiles, motorcycles are not operated and treated as passenger-cars in traffic management in Taiwan.
For example, for urban streets with three traffic lanes or more, motorcycles are not allowed to travel along the left side of the street and neither to make direct left-turn from the farthest left lane. They have to make indirect left-turns by crossing street twice separately. In order to facilitate the above- mentioned indirect left-turns, waiting zones are designated for motorcycles at some intersections. For four-approach intersections, designated waiting zones can be installed behind the curb line. However, it is rarely possible to find enough space for motorcycle waiting zone at T-intersections. Therefore, some motorcycle waiting zones are located in the way of through traffic and cause traffic conflicts.
The objective of this study is to examine problems resulted from improperly installed waiting zones for indirect left-turning motorcycles at T-intersections. Safety and speed are adopted to reflect negative impacts of motorcycle waiting zones. Factors such as sidewalk width, parking regulation, number of left-turning motorcycles, and distance to next intersection are taken into consideration for developing feasible alternatives. Finally, an operational process for improving waiting zone for left-turning motorcycles at T-intersections is proposed.