도시고속도로의 연결로 접속영향권내 평균속도 추정에 관한 연구 -부산광역시 제1도시고속도로를 대상으로

Abstract

Urban freeway is generally a high-speed roadway facility carrying the tremendous automobiles and keeping the free flow speed except for the rush hours as a primary arterial highway connected between the downtown area and the suburban area or circulated along the circumference of the suburban area in the big city. However, most of the urban freeways are suffering from severe traffic congestion due to the increased traffic volumes regardless of the rush hours. Thus, it is strongly needed to study an appropriate measure for increasing the efficiency of existing urban freeway instead of constructing the new urban freeway.

This study was to collect real-time traffic characteristic data (flow, speed, occupancy, headway, etc.) at the upstream sections, the downstream sections, and the ramp sections within the urban freeway ramp influence areas under the study, analyze the correlation between traffic characteristic data at the above sections within the urban freeway ramp influence areas, and finally suggest the optimal speed models using the traffic characteristic data within the urban freeway ramp influence areas.

From the traffic characteristic analyses, and development and verification of speed models in the urban freeway ramp junctions, the following conclusions were drawn:

ⅰ) Analysis of traffic characteristics showed that there was a distinct difference in lane-based traffic characteristics, especially higher traffic volumes, lower speed and higher density in the 2nd lane than those in the 1st lane in the urban freeway ramp influence areas.

ⅱ) Average speed within the urban freeway on-ramp influence areas showed a high correlation with upstream flow and speed, and ramp flow and speed, but average speed within the urban freeway off-ramp influence areas showed a high correlation with downstream flow and speed, and ramp speed.

ⅲ) Speed models in the urban freeway ramp influence areas under the study showed a high explanatory power with the determination coefficients() of 0.99 in the on-ramp influence areas and 0.96 in the off-ramp influence areas, respectively.

ⅳ）Speed models in the urban freeway ramp influence areas under the study proved a high correlation between observed speeds and expected speeds with the high correlation coefficients() of about 0.996 in the on-ramp influence areas and 0.938 in the off-ramp influence areas, respectively.