Examination of an Effective Sign Arrangement in an Auxiliary Lane Section of Multilane Expressways

Abstract

When an auxiliary lane is installed in an uninterrupted section of a multi-lane expressway, the climbing lane type, i.e. adding and ending the auxiliary lane from shoulder has been generally adopted, and other types including field trials have also been introduced. The lane-changing behavior is important for traffic operation in the auxiliary lane section. No research, however, has been conducted of the effect of sign arrangement on the lane-changing behavior. After analyzing the relationship between sign arrangement and lane-changing behavior in the auxiliary lane section based on video observation results, the study calibrated a microscopic simulation model that takes into account the effect of sign on lane-changing behavior, and examined the effective arrangement of the sign in the auxiliary lane section with lane addition and closure from shoulder. As a result, it was confirmed that the advance sign affects some drivers' lane-changing behavior, and that it is effective for smoothness and safety to place the advance sign at the start point and 1 km before the end of an auxiliary lane of 2 km long.