Speed Correlation Modeling within the On-Ramp Junction Influence Area of Urban Freeway

Generally urban freeway plays a key role in the urban transportation system. However, most of the urban freeways have a congestion problem on the ramp junctions. Particularly, traffic congestion used to occur within the on-ramp junction influence areas of the urban freeway during the rush hours in Korea. The purpose of this study is to collect and investigate the traffic characteristics of each lane at the upstream and downstream locations within the on-ramp junction influence area of the urban freeway, compare and analyze the traffic characteristics of each lane within the on-ramp junction influence area, and finally develop and verify the speed correlation models within the on-ramp junction influence area of the urban freeway. From the traffic characteristic analyses and the speed correlation models within the on-ramp junction influence area of the urban freeway, the following conclusions were drawn: ⅰ) Traffic characteristic analyses were shown to have a distinct difference in the lane-based characteristic distributions within the on-ramp junction influence areas. The lane-based capacities within the on-ramp junction influence areas were also found to decrease by about 5 to 30% when compared with those on the mainline locations. ⅱ) Density was shown to be a little low impact on the speed within the on-ramp junction influence areas close to the urban or suburban areas, but a little high impact on the speed within the on-ramp junction influence areas of the urban freeway between the urban and suburban areas. ⅲ) Speeds on the 1st lane at the downstream location and the 2nd lane at the upstream location were especially found to have a high correlation characteristics with that on the 2nd lane at the downstream location within the on-ramp junction influence areas of the urban freeway. ⅳ) Speed correlation models were especially to have a high explanatory power with the coefficient of determination() of about 0.7191 to 0.9738, and also were to be very valid with a high correlation coefficients() of about 0.602 to 0.945 within the on-ramp junction influence areas of the urban freeway. ⅴ) Traffic characteristics of the 2nd lane at the downstream location were found to be an important impact on those of the rest locations within the on-ramp junction influence areas, and the urban freeway traffic management system such as the ramp metering system or the variable message signs to be needed during the rush hours.Nomenclature ⅲ List of Tables ⅳ List of Figures ⅴ Abstract ⅶ 제 1 장 서 론 1 1.1 연구배경 1 1.2 연구목적 및 필요성 2 1.3 문헌연구 2 1.4 자료수집 4 제 2 장 교통특성분석 6 2.1 교통류율 6 2.2 속도 10 2.3 밀도 14 제 3 장 교통특성관계 18 3.1 교통류율과 속도 18 3.2 속도와 밀도 21 3.3 교통류율과 밀도 24 제 4 장 모형 구축 및 검증 27 4.1 모형 구축 27 4.2 모형 검증 38 제 5 장 결 론 48 참고문헌 5

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