Traffic Characteristics on Lane Drop Areas around Highway Work Zones

The capacity on lane drop area near the work zone is usually reduced comparing with basic section. It is because vehicles on the merging lane changes their direction to the adjacent lane. The decrease rate of capacity on Korean highway traffic conditions is needed. The study of capacity decrease on lane drop areas is necessary to evaluate the facility of bypass roads and to obtain travel time delays and for the purpose of traffic flow research. This study was done on uninterrupted highway work zones where the traffic queue exists at the upstream of survey points. Flow-speed relationship was modelled using the field data. The capacity calculated from the model was compared with average capacity from the survey data. The lane drop configuration is divided into two types. The first one changes from two to one lane and the second one changes from three to two lanes. The results of capacity was found as 1,500pcphpl for the former type and 1,820 pcphpl for the latter type which is equivalent to 68% and 83% of basic capacity, respectively. The former had similar capacity to foreign studies and the latter was appeared having bigger capacity by around 10%.