This handbook, which was developed in recognition of the need for the compilation and dissemination of information on advanced traffic control systems, presents the basic principles for the planning, design, and implementation of such systems for urban streets and freeways. The presentation concept and organization of this handbook is developed from the viewpoint of systems engineering. Traffic control studies are described, and traffic control and surveillance concepts are reviewed. Hardware components are outlined, and computer concepts, and communication concepts are stated. Local and central controllers are described, as well as display, television and driver information systems. Available systems technology and candidate system definition, evaluation and implementation are also covered. The management of traffic control systems is discussed.

Traffic control devices in workzones are intended to provide sufficient guidance to motorists to help prevent collisions, especially with construction operations, and based on study of their use in Illinois, they appear to be meeting the objectives. What has been discovered in assessing workzone traffic control and crashes is that collisions occur more frequently than reports show and in ways not necessarily addressed in previous studies. For the most part, traffic control devices (TCD) within the actual construction area require no changes. They are protecting the workers from the motorists. What leads to collisions inside the work area are reduced lane widths and lack of adequate escape, especially on limited access roadways. As a result, the most frequent type of collision is rear-end, often caused by drivers stopping or suddenly slowing because of distractions. Outside the work area, the problem appears more related to poor driving behavior and need for some improved guidance for motorists, especially within the merge areas. When taking into account the under-reporting of crashes, with the exception of increases in certain manners of collision such as rear-end, the crashes appear no more severe than crashes occurring outside such zones. Crashes with pedestrians (which includes workers) also appear no more likely than in locations without workzones. On the other hand, crash reporting appears unlikely to include portions of the workzone away from the actual construction area. Using a set of crash reports in which the workzone was defined clearly to include the approach, taper, and exit, analysis suggests that crashes are almost as likely to occur outside the actual construction area as within. It is these crashes outside which appeared more severe and more amenable to enhanced traffic control, especially enforcement. The report recommends practices which could reduce crashes in the approach and where changes or reductions in lanes occur. In addition to other recommendations, a model for a process to be used in generating and reviewing workzone traffic controls has been developed.

This booklet is intended to be a single information resource for currently available Technology Transfer (T2) products on the subjects of traffic control and safety in highway construction and maintenance zones. This booklet is of particular value to state and local highway engineers who are responsible for planning, managing, implementing and inspecting traffic control devices in work and maintenance zones, as well as to individuals who are in need of, or provide, continuing training on all aspects of work-zone traffic management. For each product listed, the address and telephone number of contact agencies are provided along with a brief description and the terms for acquisition.