Analysis about Relations with Road Structure and the Travel Speed in the General Road

Abstract

Road structure (component of cross section, element of alignment, etc.) is decided by the road classification (type and class) and the design speed. And the highway planning and the advanced design are carried out using these. However, this does not guarantee the function and the level of service that a road must originally take. Especially, for roads where the traffic function is particularly important, after clearly defining the target travel speed, it is necessary to examine status of achievement and possibility of achievement by road improvements. To do this, it is necessary first to quantitatively identify the factors which reduce travel speed. In this study, as part of this investigation, the relationship between road structure and travel speed was analyzed, and a correlation was found between vertical alignment, carriageway width, horizontal alignment, and travel speed. In addition, by formulating these relationships, road structure conditions that enable a certain speed to be achieved were proposed.