Intelligent Freeway Transportation Systems: Functional Design focuses on the efficient use of resources in the design of ITS. It discusses the principles of top down design starting with objectives and requirements, and provides guidance for the development and evaluation of functional design alternatives according to cost effectiveness principles. It shows how transportation planning principles such as Wardrop’s Laws and traffic diversion principles relate to functional ITS device selections and equipment locations. Methodologies for translating objectives to functional device types are provided. Application factors to identify device deployment densities (e.g. number of detectors per mile) as a function of traffic conditions are provided, as are evaluation models for evaluating the benefits of design alternatives based on traffic conditions. Design guidance and benefits evaluation include the following functions: (1) Non-recurrent congestion – Improvement of incident clearance time, (2) Non recurrent congestion – Incident information to motorists, (3) Recurrent congestion – Information to motorists, (4) Ramp metering, (5) Motorist service patrols.

This synthesis will be of interest to transportation planners, highway engineers, environmental personnel, highway design engineers, transit planners, highway administrators, and others concerned with the planning, design, and operational features of preferential high- occupancy vehicle (HOV) lanes on highways. Information is provided on the current and proposed state of the practice in North America. This synthesis describes the state of the art with respect to preferential treatment for HOVs on highways. This report of the Transportation Research Board provides information on long-distance facilities, such as barrier-separated, concurrent-flow (separated and nonseparated), and contraflow facilities, as well as on short-distance facilities, such as queue by-pass lanes. Planning, design, and operational features of each treatment are described. The issues and operating results are described, and specific case studies are included.

Intelligent Transportation Systems: Functional Design for Economical and Efficient Traffic Management provides practical guidance on the efficient use of resources in the design of ITS. The author explains how functional design alternatives can meet project objectives and requirements with optimal cost effectiveness and clarifies how transportation planning and traffic diversion principles relate to functional ITS device selections and equipment locations. Methodologies for translating objectives to functional device types, determining device deployment densities and determining the best placement of CCTV cameras and message signs are provided, as are models for evaluating the benefits of design alternatives based on traffic conditions. Readers will learn how to reduce recurrent congestion, improve incident clearance time in non-recurrent congestion, provide real-time incident information to motorists, and leverage transportation management center data for lane control through important new active transportation and demand management (ATDM) methods. Finally, the author examines exciting developments in connected vehicle technologies, exploring their potential to greatly improve safety, mobility and energy efficiency. This resource will greatly benefit all ITS designers and managers and is of pivotal importance for operating agencies performing evaluations to justify operational funding and system expansions.

Freeway ramp metering systems have been used to improve urban freeway flow. However, control strategies must be properly adjusted to account for ramp queues overflowing onto surface streets and provide equitable on-ramp control during various operating periods. An improved solution can be obtained by optimizing this problem simultaneously for a group of time slices. This study identifies and examines a microcomputer-based optimization scheme that can assist in developing efficient freeway control strategies for on-line freeway surveillance and control. A multi-level freeway control structure is employed for which ramp metering control algorithms are developed for each level of control. Flow-based and lane occupancy-based system algorithms are presented. Detailed data file requirements are provided for each control level. A microcomputer prototype, or laboratory test version of the system level, will be described in a companion project report.