Urban freeway is a primary arterial which is connected between the urban area and the suburban areas or circulated along the circumference of the suburban area in the big city. However, most of the urban freeways do not play an important role in the urban transportation system during the non-peak periods as well as the peak periods, because the urban freeways are not enough as compared with the increased traffic volumes. Additionally the design criteria of the expressway cannot be applied to the urban freeway, because the travel patterns on the urban freeway are different from those on the expressway. So it is very strongly needed to increase the efficiency of the urban freeway by suggesting the urban freeway traffic management system (UFTMS) plan with the identification of the roadway and traffic characteristics.
Thus this study is to collect and investigate the real-time roadway and traffic characteristics within the off-ramp influence area, compare and analyze the real-time roadway and traffic characteristics within the off-ramp influence area, and finally construct and suggest the optimal density predictive model within the off-ramp influence area of the urban freeway, compared with the density predictive models based on the highway capacity manual (HCM) or Korea highway capacity manual (KHCM). Based on the roadway and traffic characteristic analyses, and construction and verification of the density predictive model on the off-ramp influence area of the ramp junction of the urban freeway, the following conclusions were drawn:
ⅰ) Urban freeway traffic management system was needed to be established for reducing the traffic congestion within the off-ramp junction influence area because traffic flow was mostly concentrated on from 7:00 (AM) to 8:00(PM).
ⅱ) This model was proved to have a high explanatory power with the determinant coefficient of 0.931 and also show a high correlation with the correlation coefficient of 0.965 between the variables.
ⅲ) This model was proved to be much fitter for the roadway and traffic characteristics on the urban freeway, compared with the existing density models suggested by the highway capacity manual (HCM) or Korea highway capacity manual (KHCM).