도시고속도로의 유출입연결로 접속영향권에서 차로별 용량평가에 관한 연구

Abstract

Urban freeway is defined as the roadway with 4 lanes or more which requires a high design criteria for handling a large capacity of vehicles rapidly as a high-speed exclusive roadway in the city. However, most of the urban freeways suffer from severe traffic congestion due to the increased traffic exceeding their capacities regardless of the morning and afternoon rush-hours or the inbound and outbound directions.

The purpose in this study is to collect and investigate the real-time traffic characteristics within the ramp junction influence areas of the urban freeway, compare and analyze the traffic characteristic relationship for each lane within the ramp junction influence areas of the urban freeway, and finally assess and suggest the optimal capacity for each lane within the ramp junction influence area of the urban freeway.

By analyzing the real-time traffic characteristics and assessing the capacity for each lane within the ramp junction influence area of the urban freeway, the following conclusions were drawn:

ⅰ) Traffic characteristics within the ramp junction influence area were found to have a distinct difference between the urban and suburban areas, the upstream and downstream locations, or the 1st lane and 2nd lane within the ramp junction influence area in the inbound and outbound directions of the urban freeway.

ⅱ) Correlation analyses were found to have a high coefficient of determination() of about 0.8 or more between the flow and speed, a considerable high coefficient of determination() of about 0.6 or more between the speed and density, and a very high coefficient of determination() of about 0.9 or more between the flow and density.

ⅲ) Capacity characteristics were found to be more traffic on the 1st lane than the 2nd lane, in the urban areas than the suburban areas, and at the downstream location than the upstream locations within the ramp junction influence area of the urban freeway by showing the parabolic relationship between flow and density.

ⅳ) Lane-based capacities were found to decrease by about 60% within the on-ramp junction influence areas in the inbound direction, about 40% or more within the on-ramp junction influence areas in the outbound direction and about 50% or more within the off-ramp junction influence areas in the outbound direction.

ⅴ）Lane-based capacities were found to decrease by about 40% at the upstream locations and about 10% or more at the downstream locations within the on-ramp junction influence areas in the inbound direction and about 20% or more at downstream locations within the off-ramp junction influence areas in the outbound direction.