Abstract
This paper deals with traffic congestion phenomena which are caused at sag sections on motorways by excessive traffic demand. The objective of this study is to identify the conditions which give rise to the traffic congestion phenomena at sag sections. This phenomena is dependent upon the drivers' behaviour which can be influenced by road alignments, road structures and traffic conditions and so on.
Several factors which are effective to the occurence of traffic congestion phenomena at sag sections are examined, and the quantitative conditions are identified. Finally the possible approaches to control the occurence of the phenomena are discussed.
