2017 Volume 3 Issue 4 Pages A_74-A_83
This study is aimed at statistically analyzing the detailed factors and mechanisms which might cause velocity drops in free flow condition. This study focuses on the influence of road alignment, structure and traffic characteristics upon the velocity changes of flow utilizing ETC 2.0 probe data with spatially and temporally higher resolution than the conventional data. The target section is between Kawasaki IC and Atsugi IC of Tomei Expressway including Yamato TN with heavy traffic jams frequently observed due to sag section. After a basic analysis using the contour diagram of speed profile, a regression analysis is applied for average speed and the estimated parameters suggest the significant influence of cumulative effect of up slope and merging and diverging points upon velocity variation. Finally Bayesian Network is applied for travel trajectories provided by ETC 2.0 probe data aiming at realizing the factors which might lead to higher probability of velocity drop.
