The Law of Peak-Hour Expressway Congestion

Abstract

This paper examines peak-hour traffic congestion and the nature of its relationship to traffic equilibrium theory as supported by Down's Law of Peak-Hour Traffic Congestion. This Law states that on urban commuter expressways, peak-hour traffic congestion rises to meet maximum capacity. A complex set of forces lie behind this Law, which are analyzed by presentation of a model of commuter decision-making and its underlying set of assumptions. Traffic equilibrium is further discussed and illustrated through 3 commuting scenarios or cases: 1) a city with automobile-driving commuters only; 2) a city with both automobile-driving and bus-riding commuters; and 3) a city with segregated track public transit and automobile-driving commuters.