Observations on the fundamental diagram and their interpretation from the human factors perspective

Abstract

Some observations are made on the fundamental diagram of freeway traffic,among which are three influence regions, three types of transition around capacity, and a capacity drop phenomenon. This research aspires to interpret these observations from the human factors perspective in traffic flow theory. A combination of these factors shapes the above-mentioned influence regions, transition around capacity, and capacity drop. Of critical importance in determining the transition around capacity and capacity drop is drivers' aggressiveness, a factor that has long been overlooked in the past. This paper provides a detailed account of where it comes from and how it influences the fundamental diagram.