Chapter One Introduction 1. 2 What is traffic control system Traffic control systems are the most visible element of the urban infrastructure They are not just physical systems like telephones or sewers or streets although their technological elements, traffic lights, signs, and painted pavements, fit that description. Rather, they are systems that attempt to impose a strong social control over the most fundamental of human behaviors whether to move or be still. Traffic engineers must control police, drivers, and pedestrians. For most other elements of the urban infrastructure, controlling the behavior of users did not constitute the primary goal of designers. 1 For traffic engineers, understanding and manipulating the behavioral patterns of drivers and pedestrians proved to be a more important problem than the control mechanisms themselves. Traffic engineers learned rapidly to pay careful attention to ergonomics(人机工程学), the inter face between people and machines1.2 What is traffic control system: Traffic control systems are the most visible element of the urban infrastructure. They are not just physical systems like telephones or sewers or streets, although their technological elements, traffic lights, signs, and painted pavements, fit that description. Rather, they are systems that attempt to impose a strong social control over the most fundamental of human behaviors, whether to move or be still. Traffic engineers must control police, drivers, and pedestrians. For most other elements of the urban infrastructure, controlling the behavior of users did not constitute the primary goal of designers.1 For traffic engineers, understanding and manipulating the behavioral patterns of drivers and pedestrians proved to be a more important problem than the control mechanisms themselves. Traffic engineers learned rapidly to pay careful attention to ergonomics (人机工程学), the interface between people and machines