Intelligent Vehicle Highway Systems Research Articles

Determination of Number of Probe Vehicles Required for Reliable Travel Time Measurement in Urban Network

Several intelligent vehicle–highway system demonstration projects are currently assessing the feasibility of using probe vehicles to collect realtime traffic data for advanced traffic management and information systems. They have used a variety of criteria to determine the number of probes necessary, but few generalizable algorithms have been developed and tested. The described algorithm explicitly considers the time period for travel time estimation (e.g., 5, 10, or 15 min), the number of replications of travel time desired for each link during each measurement period (reliability criterion), the proportion of links to be covered, and the length of the peak period. This algorithm is implemented by using a simulation of the Sacramento Network (170 mi2) for the morning peak period. The results indicate that the number of probe vehicles required increases non-linearly as the reliability criterion is made more stringent. More probes are required for shorter measurement periods. As the desired proportion of link coverage in the network increases, the number of probes required increases. With a given number of probes a greater proportion of freeway links than of major arterials can reliably be covered. Probe vehicles appear to be an attractive source of real-time traffic information in heavily traveled, high-speed corridors such as freeways and major arterials during peak periods, but they are not recommended for coverage of minor arterials or local and collector streets or during off-peak hours.

Determination of Number of Probe Vehicles Required for Reliable Travel Time Measurement in Urban Network

Several intelligent vehicle—highway system demonstration projects are currently assessing the feasibility of using probe vehicles to collect realtime traffic data for advanced traffic management and information systems. They have used a variety of criteria to determine the number of probes necessary, but few generalizable algorithms have been developed and tested. The described algorithm explicitly considers the time period for travel time estimation (e.g., 5, 10, or 15 min), the number of replications of travel time desired for each link during each measurement period (reliability criterion), the proportion of links to be covered, and the length of the peak period. This algorithm is implemented by using a simulation of the Sacramento Network (170 mi2) for the morning peak period. The results indicate that the number of probe vehicles required increases nonlinearly as the reliability criterion is made more stringent. More probes are required for shorter measurement periods. As the desired proportion of li...

Visual tracking for intelligent vehicle-highway systems

The complexity and congestion of current transportation systems often produce traffic situations that jeopardize the safety of the people involved. These situations vary from maintaining a safe distance behind a leading vehicle to safely allowing a pedestrian to cross a busy street. Environmental sensing plays a critical role in virtually all of these situations. Of the sensors available, vision sensors provide information that is richer and more complete than other sensors, making them a logical choice for a multisensor transportation system. We propose robust detection and tracking techniques for intelligent vehicle-highway applications where computer vision plays a crucial role. In particular, we demonstrate that the controlled active vision framework can be utilized to provide a visual tracking modality to a traffic advisory system in order to increase the overall safety margin in a variety of common traffic situations. We have selected two application examples, vehicle tracking and pedestrian tracking, to demonstrate that the framework can provide precisely the type of information required to effectively manage the given traffic situation.

Emerging technologies in control engineering

Provides an overview of emerging technologies that are expected to become major areas of application for control systems technology. The technologies that were selected were chosen because of their importance (especially in economic terms) and because of their relevance to the field of control. They are: intelligent vehicle highway systems; semiconductor manufacturing; mechatronics; and microelectromechanical systems. >

Dynamic vehicle routing: Status and prospects

Although most real-world vehicle routing problems are dynamic, the traditional methodological arsenal for this class of problems has been based on adaptations of static algorithms. Still, some important new methodological approaches have recently emerged. In addition, computer-based technologies such as electronic data interchange (EDI), geographic information systems (GIS), global positioning systems (GPS), and intelligent vehicle-highway systems (IVHS) have significantly enhanced the possibilities for efficient dynamic routing and have opened interesting directions for new research. This paper examines the main issues in this rapidly growing area, and surveys recent results and other advances. The assessment of possible impact of new technologies and the distinction of dynamic problems vis-a-vis their static counterparts are given emphasis.

Measuring IVHS impacts using computer spreadsheet programs

In the future, increases in roadway capacity will be achieved using advanced technologies such as computerized signal systems, ramp metering systems, and motorist information systems. These systems are far different from the traditional approach of roadway widening or new roadway construction. Unlike their “dirt and asphalt” predecessors, the implementation of advanced technologies or Intelligent Vehicle Highway Systems (IVHS) will provide flexible and multiple uses of technology to improve travel conditions. For example, signal systems traditionally seek to improve recurring congestion through better coordination of signal timing patterns. They typically use only two to three timing schedules a day and are rigidly structured to provide the same timing schedule for extended periods of time. With recent technological advances, IVHS signal systems will be better able to respond to a wide range of potential traffic demands during any time of the day. In addition, their traffic surveillance equipment could also be used to provide data for systems designed to relay traffic information to motorists. This paper will explore the use of computer spreadsheet programs in developing a model to measure IVHS impacts. It will discuss how key traffic parameters can be readily incorporated into database models, as well as the flexibility and potential provided by these database models to assist with measuring the impacts of the IVHS.

Intelligent Vehicle Highway System: Advanced Public Transportation Systems

A major program of the Intermodal Surface Transportation Efficiency Act of 1991 [1] is the Intelligent Vehicle-Highway System (IVHS). This program seeks technological methods to increase the capacity of the existing transportation infrastructure. Although private automobiles are the major focus of the IVHS program, it also seeks improvements in the public transportation system. This paper addresses the public transportation component, known as the Advanced Public Transportation System (APTS). A future vision of an Advanced Public Transportation System is presented, providing a unifying framework for the proposed enhancements to user services. A “bus hub” structure is presented that increases the quality and attractiveness of the system for users, operators, and traffic managers. Also, the importance of APTS to the goals of the IVHS program are discussed.

Intelligent vehicle highway systems: A mandate now—and for the future

The operation of large commercial vehicles, especially in congested urban environments, presents a different set of problems than that experienced by automobile drivers. The constraints of size, length, weight, height, and time provide additional challenges for the commercial driver. Vehicle communication and location monitoring are necessary to maximize productivity in a highly competitive marketplace. Commercial vehicle tracking and communication systems are enjoying spectacular growth, but a land navigation system for major urban areas is also needed. Future developments of other IVHS-related technologies, many listed in the following article, will contribute significantly to further productivity gains and should also contribute to a safer environment within which automobiles and large commercial vehicles can better coexist.

Computing and modeling issues in wide-area Advanced Traveler Information Systems

Advanced Traveler Information Systems (ATIS) is a primary component of Intelligent Vehicle Highway Systems (IVHS) under development to improve safety and efficiency of automobile and truck travel. An ATIS is fundamentally a wide-area mobile computing environment involving large numbers of dispersed travelers, many of whom have portable computing capabilities, and who use wireless channels to communicate with databases on remote servers. Successful deployment of such systems requires solutions to several problems in distributed database management, telecommunications, algorithms, and visualization. In addition, there are problems involving integration of these technologies to provide large-scale, end-to-end solutions with acceptable real-time performance. In this paper, we describe a number of these problems, and associated needs for analysis, simulation, and modeling. Example problems of importance include allocation of data among stationary servers and mobile computers, distributed queuing strategies under high-demand and limited bandwidth conditions, routing and route guidance algorithms under constraints, and real-time regridding for updating multiple-layer graphical displays.

Global positioning systems in the time domain: How useful a tool for intelligent vehicle-highway systems?

Much of the research and development work in intelligent vehicle-highway systems (IVHS) relies on the availability of methods for locating and monitoring vehicles (e.g. “probe vehicles”) in real time across a road network. This paper considers the use of the global positioning system (GPS) as one method for obtaining information on the position, speed and direction of travel of vehicles. It reports the results of a series of field studies, in which real-time GPS data were compared to data collected by an instrumented vehicle, under a range of physical and traffic conditions. The field studies and consequent data analysis provide a picture of the reliability and usefulness of GPS data for traffic monitoring purposes, and hence the possibilities for the use of GPS in IVHS projects. The use of GPS receivers tailored for mobile applications, and able to provide direct observations of vehicle speed and travel direction, coupled with database management using geographic information systems (GIS) software, was found to provide a reliable and efficient system for vehicle monitoring. Field data collection under “ideal” GPS conditions indicated that accurate speed and position data were readily obtained from the GPS. Under less favourable conditions (e.g. in downtown networks), data accuracy decreased but useful information could still be obtained. In addition, the conditions and situations under which GPS data errors could be expected were noted. The finding that it is possible to relate standard GPS signal quality indicators to increased errors in speed and position provides an enhanced degree of confidence in the use of the GPS system for real-time traffic observations.

4.5.3 ETHICS IN SYSTEMS ENGINEERING

AbstractSystems are growing larger and larger and are taking over the running of many facets of modern society, such as Automated Traffic Handling Systems, Intelligent Vehicle Highway Systems, and Air Traffic Control Systems. A failure in one of these systems can cause economic damage, as well as loss of life. An engineer who discovers such a problem or even the probability of such a problem faces an ethical dilemma concerning what to about the discovery. This paper discusses personal and corporate ethics in systems engineering; the ethical dilemma faced by a systems engineer and the possible consequences of abiding by one's principles.

Direction finding and "smart antennas" using software radio architectures

Operational tests and demonstrations of systems based on software radios are currently being performed in the 800 MHz mobile cellular radio band. These field trials are for mobile unit geolocation systems and adaptive phased array "smart antenna" applications. The geolocation system trials are in response to the demand for high confidence geolocation of mobile units for enhanced emergency 911 service and for use in the US Department of Transportation's Intelligent Vehicle Highway System (NHS) initiative. The smart antenna array application addresses the cellular service providers' need for more user channel capacity and/or geographic coverage from existing base station installations. Software radio architectures were selected because of their ability to provide superior performance at low life cycle cost. These systems use 4 to 8 wideband coherent channels and fully characterize the arriving RF energy to either geolocate the emitter or to maximize the carrier-to-interference ratio.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Vehicle Control Issues in Intelligent Vehicle Highway Systems

This paper gives an overview of vehicle control issues associated with Intelligent Vehicle Highway Systems (IVHS), in particular it treats the technology required for autonomous control of vehicles in an Automated Highway System (AHS). This is not a true survey paper in that research results of the California PATH program are presented, whereas ongoing work in Europe (Prometheus) and Asia is not treated. The primary issues dealt with in this paper concern the longitudinal and lateral control of autonomous vehicles.

From Chinese Chariots to Smart Cars: 2,000 Years of Vehicular Navigation

The odometer and differential odometer date back approximately 2,000 years, perhaps 1,000 years before the magnetic compass appeared. Gyroscopic devices were first described in the mid-1800s. Automatic mechanical route guides, which began appearing around 1910, introduced the concept of real-time turn-by-turn route guidance to early automobile drivers. The first vehicular navigation system to incorporate electronics was developed during World War II. A research project of the late 1960s established concepts for dynamic route guidance based on realtime traffic conditions. Satellite positioning and digitized road maps also originated in the 1960s. Map-matching software for reconciling measured vehicle paths with digitized road maps to remove position errors was invented in 1970. Thus the basic technologies were already in place when the microprocessor emerged in the 1970s to facilitate their integration in the sophisticated automobile navigation and route guidance systems that finally reached the market in the late 1980s. This paper reviews the historical background and then focuses on the last 25 years during which automobile navigation and route guidance systems achieved a degree of technological maturity and blossomed into the centerpiece of the worldwide intelligent transportation systems (ITS), known until recently as intelligent vehicle-highway systems (IVHS).

CELLULAR DIGITAL PACKET DATA FOR INTELLIGENT VEHICLE HIGHWAY SYSTEMS

For Intelligent Vehicle Highway Systems (IVHS) to be a reality, a communication system, which can provide reliable communication capability in mobile environment, is needed. A cellular system capable of supporting data traffic, can satisfy many of the IVHS communication requirements; such as traveller information and traffic management, public transit monitoring and control, fleet management, truck monitoring, hazard and collision warning. Cellular Digital Packet Data (CDPD) is a data transmission service which coexists with current cellular systems in the same frequency band and is presently being deployed. In this paper, we briefly summarize the salient features of CDPD system and evaluate its data transmission capacity. We also study suitability of CDPD for IVHS applications. Our study suggests that CDPD is capable of satisfying many of the functional requirements of IVHS. Furthermore, a mature IVHS system (with 50% penetration) will need approximately 36.5% of the capacity of CDPD system, even when the cellular system with which CDPD coexists, operates at its 2% Erland Capacity. With lesser penetration of IVHS, even smaller percentage of CDPD capacity will be needed. In conclusion, CDPD seems to be a promising technology for IVHS and should be further explored.

Statistical characterization of Rician multipath effects in a mobile-to-mobile communication channel

A statistical model is developed for a narrowband mobile-to-mobile channel taking into consideration Rician scattering near receiving and transmitting antennas both individually and concomitantly. From the proposed channel model we obtain the probability density function of the received signal envelope, the time correlation function and RF spectrum of the received signal, and level crossing rates and average fade durations. We briefly discuss the impact of these parameters on communication networks supporting an intelligent vehicle highway system (IVHS).

The Realizability of the Potential Benefits of Intelligent Vehicle‐highway Systems

Intelligent vehicle‐highway systems (IVHS) combine computing, sensors and telecom‐munications to deliver a more effective road/vehicle system for freight and passenger vehicles. Many of these technologies involve surveillance of the location and behaviour of identified vehicles and/or people, and the collation of such data for further use. These and other aspects of IVHS technologies raise concerns among the community, and have delayed the adoption of some systems. Outlines IVHS systems, and considers strategies for their introduction. The ownership and use of data collected in the course of IVHS operations is shown to present opportunities relating to revenue‐collection and law‐enforcement, on the one hand, and public acceptability problems, on the other. There are growing links with large‐scale data transmission facilities such as the US National Information Initiative (NII) and the equivalent massive interactive data networks developing elsewhere. Major errors in the implementation of early elements of IVHS may make it extremely difficult to deploy further elements. Argues that adoption of a number of principles could safeguard the potential benefits at an acceptable social cost.

Social Choice about Privacy: Intelligent Vehicle‐highway Systems in the United States

Broad coalitions of companies, governments, and research institutions in several countries are currently designing massive electronic infrastructures for their roadways. Known collectively as intelligent vehicle‐highway systems (IVHS), these technologies are intended to ease toll collection and commercial vehicle regulation, provide drivers with route and traffic information, improve safety and ultimately support fully automated vehicles. Although many aspects of IVHS are uncertain, some proposed designs require the system to collect vast amounts of data on individuals′ travel patterns, thus raising the potential for severe invasions of privacy. To make social choices about IVHS, it is necessary to reason about potentials for authoritarian uses of an IVHS infrastructure in the hypothetical future. Yet such reasoning is difficult, often veering towards Utopian or dystopian extremes. To help anchor the privacy debate, places IVHS privacy concerns in an institutional context, offering conceptual frameworks to discuss the potential interactions between IVHS technologies and the computer design profession, standards‐setting bodies, marketing organizations, the legal system and government administrative agencies.

Emerging technologies in control engineering

Provides an overview of emerging technologies that are expected to become major areas of application for control systems technology. The technologies that were selected were chosen because of their importance (especially in economic terms) and because of their relevance to the field of control. They are: intelligent vehicle highway systems; semiconductor manufacturing; mechatronics; and microelectromechanical systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

IVHS/AHS: driving into the future

Intelligent vehicle highway systems (IVHS) involve the systems integration of many emerging technologies to effectively address the needs, both present and future of the nation's roadway complex. An introduction to and brief history of IVHS is presented. Then, a more detailed overview of automated highway systems (AHS), the part of IVHS of most interest to control engineers, is given. One focus is on various control issues that must be confronted before an AHS is deployed. >