Showing papers on "Intelligent transportation system published in 2000"

Mobile phone location determination and its impact on intelligent transportation systems

Abstract: Research and development on the technologies of locating the mobile (wireless) phone caller have been rapidly gaining momentum around the world. Once these technologies are mature enough to be deployed, they will have significant impact on automotive telematics and modern public transit systems. In this paper, we discuss why locating mobile phones becomes a hot topic among telecommunications giants, what technologies are being studied and standardized, when we are going to see the actual deployment, and what services they may provide? We then consider its potential impact on future intelligent transportation systems, including telematics and public transit systems. Many of us have already recognized how important a role the communications systems play in modern transportation. In the near future, if every mobile phone is able to determine its location, advances in our current transportation systems become inevitable.

Summary of Vehicle Detection and Surveillance Technologies used in Intelligent Transportation Systems

Abstract: This summary document was developed to assist in the selection of vehicle detection and surveillance technologies that support traffic management and traveler information services. Included are descriptions of common types of vehicle detection and surveillance technologies in terms of theory of operation, installation methods advantages and disadvantages,and summary information about performance in clear and inclement weather and relative cost. Under intrusive technologies, the following are described: pneumatic road tube inductive loop detectors, piezoelectric sensors, magnetic sensors, and weigh in motion (WIM). In the non-intrusive category, these technologies are described: video image processor, microwave radar infrared sensors, ultrasonic sensors, and passive acoustic array sensors. Following each technology description is vendor-provided information about specific sensor models, their functions and applications, users,and installation and maintenance costs

GPS-based message broadcast for adaptive inter-vehicle communications

Abstract: The intelligent transportation systems (ITS) use advanced communications and control technologies to improve current transportation systems. To achieve many ITS applications, the ability to exchange messages between vehicles is necessary. This is generally required as inter vehicle communication (IVC). IVC can be considered as a special case of ad hoc networks, where nodes only move along predefined road paths. We propose new broadcast protocols that make use of global positioning system (GPS) information to enhance the performance of broadcast service in IVC. The ability to efficiently broadcast messages is necessary for any communications in IVC (e.g, updating routing tables, etc). We propose two algorithms that effectively reduce the number of re-broadcast messages without affecting the number of hosts (vehicles) that receive the broadcast. The simulation results show up to several hundred percentage of bandwidth utilization improvement can be achieved by our proposed broadcast protocols.

GIS Software for Measuring Space-Time Accessibility in Transportation Planning and Analysis

Abstract: Transportation systems exist to improve individual accessibility. However, emerging applications of GIS in transportation (GIS-T) and intelligent transportation system (ITS) focus on throughput (the amount of system flow) rather than accessibility. Throughput is related but not equivalent to accessibility. Sensitive transportation planning requires rigorous, realistic and tractable accessibility measures. This paper reports on the development of GIS software that implement space-time accessibility measures (STAMs). The STAMs reflect the benefits that individuals receive from the transportation system. They are easily interpreted, particularly with respect to changes in accessibility. The STAMs also consider the locations and travel velocities dictated by the transportation system as well as individuals’ daily activity schedules. Tractable computational procedures allow calculation of the STAMs for detailed, urban-scale transportation networks. A prototype ArcInfo^®-linked software system that runs on Windows NT^® or Sun Solaris^® platform implements the STAMs with user-friendly interfaces and project management tools.

GPS-based message broadcasting for inter-vehicle communication

Abstract: Intelligent Transportation Systems (ITS) have become a focus for many countries. To achieve ITS, Inter Vehicle Communication (IVC) is required for the exchange and distribution of data such as congestion or emergency information. If this communication can be done without fixed infrastructure, the systems can be deployed quickly and on a larger scale. Ad hoc networking technologies are one such technology to achieve IVC. However, if generic ad hoc network solutions are applied directly to IVC, performance can degrade quickly as the system scales particularly for broadcast type messages. In this paper we propose two new broadcast protocols that reduce bandwidth required for broadcast communication by taking advantage of a vehicle's highly directional movement and Global Positioning Information. To show the performance of our new protocols, we compare our approach with generic ad hoc broadcasting techniques. Our results show that it is possible to achieve several hundred percent improvement of bandwidth utilization with very slight sacrifice of reachability.

An Internet-based geographic information system that integrates data, models and users for transportation applications

Abstract: This paper is concerned with the development of an Internet-based geographic information system (GIS) that brings together spatio-temporal data, models and users in a single efficient framework to be used for a wide range of transportation applications – planning, engineering and operational. The functional requirements of the system are outlined taking into consideration the various enabling technologies, such as Internet tools, large-scale databases and distributed computing systems. Implementation issues as well as the necessary models needed to support the system are briefly discussed.

Real-time differential carrier phase GPS-aided INS

Abstract: This article describes the implementation and experimental results of a real-time carrier phase differential Global Positioning System (GPS) aided inertial navigation system (INS). The implementation is the result of a study to analyze the capabilities of such a system relative to the requirements of advanced vehicle control and safety systems for intelligent transportation systems. Such navigation systems have many application possibilities (e,g., aviation and precision flight, automated mining, precision farming, dredging, satellite attitude control). Advantages and disadvantages of the GPS, INS, and differential GPS-aided INS approaches are discussed. The implementation achieves 100-Hz vehicle state estimates with position accuracies at the centimeter level through the use of differential carrier phase GPS techniques.

Requirements for Evaluating Traffic Signal Control Impacts on Energy and Emissions Based on Instantaneous Speed and Acceleration Measurements

Abstract: The evaluation of many transportation network improvements commonly is conducted by first estimating average speeds from a transportation or traffic model and then converting these average speeds into emission estimates based on an environmental model such as MOBILE Unfortunately, recent research has shown that certainly average speed and perhaps even simple estimates of the amount of delay and the number of stops on a link are insufficient measures to fully capture the impact of intelligent transportation system strategies such as traffic signal coordination In an attempt to address this limitation, the application of a series of multivariate fuel consumption and emission prediction models is illustrated, both within a traffic simulation model of a signalized arterial and directly to instantaneous speed and acceleration data from floating cars traveling down a similar signalized arterial The application of these multivariate relationships is illustrated for eight light-duty vehicles, ranging in size f

An evaluation of traffic simulation models for supporting its development

Abstract: In this report, the authors evaluate existing traffic simulation models in order to identify those models that can be potentially applied in Intelligent Transportation Systems (ITS) equipped networks. The models are categorized according to type (macroscopic microscopic, or mesoscopic), as well as functionality (highway signal, integrated). The evaluation is conducted through two steps: initial screening and in-depth evaluation. From the research, it is concluded that the CORSIM and INTEGRATION models appear to have the highest probability of success in real-world applications. The authors also find that by adding more calibration and validation in the U.S., the AIMSUN 2 and the PARAMICS models will be brought to the forefront in the near term for use with ITS applications.

A Wireless Sensor Network for Smart Roadbeds and Intelligent Transportation Systems

Abstract: We have developed a wireless sensor package to instrument roadways for Intelligent Transportation Systems. The sensor package counts passing vehicles, measures the average roadway speed, and detects ice and water on the road. Clusters of sensors can transmit this information in near real-time to wired base stations for use controlling and predicting traffic, and in clearing road hazards. The sensor package draws a maximum time-averaged current of 17 tA from an internal lithium battery, allowing it to operate in the roadbed for at least 10 years without maintenance. The nodes cost well under $30 to manufacture, and can be installed without running wires under the road, facilitating wide deployment. Unlike many other types of traffic sensors, these sensors count vehicles in bumper-to-bumper traffic just as well as in widely separated traffic. The devices detect vehicles by detecting the perturbations in the Earth's magnetic field caused by the vehicles. They measure this perturbation using an anisotropic magnetoresistive magnetic field sensor. The radio transmitters in the sensor are frequency-agile, and the sensors use a randomized sparse TDMA protocol, which allows several transmit-only devices to share a channel. The sensor package includes a custom-designed, compact, broadband, inexpensive printed circuit microstrip antenna for the 915 MHz U.S. ISM band. We built a prototype sensor package, and installed it in a pothole in a city street. We used the sensor to monitor the traffic flow rate during free-flowing traffic and a traffic jam. Thesis Supervisor: Joseph Paradiso Title: Principal Research Scientist, MIT Media Lab

Intelligent transportation systems: the role of third generation mobile radio networks

Abstract: A synthetic review is given of the research developed in the past 10 years in the field of short-range communications for intelligent transportation systems. Moreover, the role of new packet mobile radio (such as the General Packet Radio Service) and third-generation systems in the possible provision of services for the field of ITS is discussed; more precisely, the services for driving safety are addressed. The research programs under development in Italy and Japan which can have an impact on the selection of suitable techniques for ITS services are presented.

Statistic and knowledge-based moving object detection in traffic scenes

Abstract: The most common approach used for vision-based traffic surveillance consists of a fast segmentation of moving visual objects (MVOs) in the scene together with an intelligent reasoning module capable of identifying, tracking and classifying the MVOs in dependency of the system goal. In this paper we describe our approach for MVOs segmentation in an unstructured traffic environment. We consider complex situations with moving people, vehicles and infrastructures that have different aspect model and motion model. In this case we define a specific approach based on background subtraction with statistic and knowledge-based background update. We show many results of real-time tracking of traffic MVOs in outdoor traffic scene such as roads, parking area intersections, and entrance with barriers.

Advanced public transportation systems: the state of the art update 2000

Abstract: This report documents work performed under FTA's Advanced Public Transportation Systems (APTS) Program, a program structured to undertake research and development of innovative applications of advanced navigation, communication, information, computer and vehicle technologies that most benefit public transportation. This report is the latest in a series of state-of-the-art reports, the last of which was published January 1998. It contains the results of an investigation of the extent of adoption of advanced technology in the provision of public transportation services in North America. It focuses on some of the most innovative or comprehensive implementations, categorized under five types of service/technologies: Fleet Management, Traveler Information, Electronic Fare Payment, Transportation Demand Management, and Intelligent Vehicle Initiative. The objective of the effort was to increase the industry's knowledge of successful applications of advanced technologies with the expectation that this will lead to their widespread adoption.

Efficient use of digital road map in various positioning for ITS

Abstract: There are many R&D improvements on positioning systems for ITS (intelligent transportation systems) adopting GPS, cellular phones or other communication systems. But, a position from any signal is always corrupted to a few meters through several hundreds of meters because of multipath, atmospheric delay, NLOS (non-line-of-sight), low DOP and so on. When the positioning systems are employed for ITS, a digital road map can be used together to display their navigation solutions in most ITS applications. Due to the fact that land-vehicles almost always run on roads, most of CNS (car navigation systems) translate the measured position onto a road. This methodology called map-matching, if it depends on a contaminated position due to white noise and biased error, has not only low accuracy but also the road ambiguity problems in some crossroads. Therefore, this paper presents an efficient use of an advanced map-matching in order to get a more improved accuracy, which estimates a large bias being the main source of errors and corrects a vehicle's position. It is composed of a modeling of biased error and filtering by a Kalman filter. We have applied the proposed map-matching to not only GPS navigation but also CDMA location. The proposed approach represents that in addition to its original visual display, an accurate digital road-map can improve the positioning accuracy effectively by correcting the vehicle's position.

Propagation prediction techniques and antenna modeling (150 to 1705 kHz) for intelligent transportation systems (ITS) broadcast applications

Abstract: This paper discusses the basic aspects of radio-wave propagation and antenna modeling at 150 to 1705 kHz The paper contains descriptions of both sky-wave and ground-wave propagation-prediction models, in addition to the methodology used to analyze antennas that operate in this band A method of calculating and normalizing antenna gain for system computations is also discussed The sky-wave models described in this paper are valid from 150 to 1705 kHz The ground-wave models described in this paper are valid from 10 kHz to 30 MHz The propagation of radio waves from 150 to 1705 kHz includes both a ground wave and a sky wave, and is quite different from propagation at any other frequency The methods used for antenna modeling and analysis in this band are also quite unlike those in other bands The AM broadcast band of 535 to 1605 kHz is planned to be used in the advanced traveler information systems (ATIS) of intelligent transportation systems (ITS), to provide information such as road conditions, road hazards, weather, and incident reporting for rural travelers The band of frequencies from 285 to 325 kHz is presently being used in another application of ITS, called the Differential Global Positioning System (DGPS), which will be used for precision location of vehicles The propagation-prediction models and antenna-analysis methods described here can be used for designing systems and making performance predictions for both of these ITS applications, or for any other systems that operate in this band of frequencies from 150 to 1705 kHz Some examples of comparisons of measured and predicted data are also presented A computer program that includes all of these propagation-prediction models and antenna-modeling techniques was used

Behavioral adaptation, safety, and intelligent transportation systems

Abstract: It is intrinsic to human nature to modify behavior to suit new conditions. How drivers are likely to change the way they drive if their vehicles are equipped with intelligent transportation system (ITS) devices is considered. It is clear from the antilock braking system experience that improvements in safety cannot be predicted on the basis of proof-of-concept studies alone, in which one simply looks at changes in performance of the task being aided, whether that is braking, navigation, or detection of hazards. One also must look at changes in other aspects of the driving task and at the type of driving being done to determine the likely effect on safety. In particular, one should assume that there may be trade-offs of mobility for safety, that is, more driving in more difficult conditions and at higher speeds leading to more crashes. Further, one should expect drivers to attempt to increase productivity while driving, given reduced driving task demand. The prolific use of cellular phones is evidence of t...

Automation of task processes: An example of intelligent transportation systems

Abstract: The sophistication of advanced automated technologies offer unprecedented opportunities to improve system and operator safety, efficiency, and comfort. However, these applications fundamentally alter the task process by virtue of the degree of automatic control these systems may exert over levels of the task (i.e., control, tactical, strategic). This article presents a discussion of the possible deleterious effects of automated technology in the transport context in relation to Intelligent Transport Systems (ITS). The potential deleterious effects of ITS include (a) shifting the driver out-of-the-loop, such that situation awareness and responsiveness to critical events may be impaired, and (b) behavioral adaptation that undermines system effectiveness. Examples of both effects are presented in relation to an evaluation of an experimental Adaptive Cruise Control system. The importance of considering these effects as part of a formal evaluation protocol is identified in order to maximize the design benefits of ITS. A framework and methodology for the evaluation of automated systems is proposed. © 2000 John Wiley & Sons, Inc.

A national strategy

Abstract: This document sets forth a comprehensive strategy for dealing with the critical problem of invasive species in the United States. Developed within the context of the National Invasive Species Management Plan (as called for by Presidential Executive Order 13112), and with the support of regional chiefs and representatives of the Fulfilling the Promise team, this National Strategy will provide clear guidance to regional and field offices as they conduct invasive species management efforts. It will also make us better neighbors to our external partners at the local, state, and federal level. The National Strategy provides specific action items to achieve the following four invasive species management goals: 1. Increase awareness; 2. Reduce the impacts to refuge habitats; 3. Reduce impacts to neighboring lands; and 4. Use and develop new integrated pest management approaches. This document consists of two interrelated parts: Current Status and Tools and Recommendations. Part I: Current Status This section reviews current invasive species management practices in the Refuge System. It identifies deficiencies, chiefly limited staff, infrastructure, and support. It then recommends that dedicated staff positions be increased at all levels, that information technology processes be updated and implemented across the Refuge System, and that support be increased at both the regional and national levels. Additional staff in the field would support early detection/rapid response, prevention and control, and sustained management activities; additional regional and national staff would improve internal communication and coordination, raise awareness, provide technical support, and strengthen the financial base. Part II: Tools and Recommendations This section presents plans and processes to achieve the goal of long-term, sustained management of invasive species. Invasive species are widespread and extremely damaging to native ecosystems. Examples of invasive species An Ainvasive species@ is defined by the Executive Order as a species that is 1) non-native (alien or exotic) to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health. Invasive species are, collectively, the single greatest threat to native plants, fish, and wildlife with the potential to degrade entire ecosystems. Based on national interagency estimates, more than six million acres of the Refuge System are infested with exotic plants. Nearly 50% of all refuges report that such infestations interfere significantly with their wildlife management objectives. Aquatic invasive species are particularly damaging to refuge habitat management efforts since most refuges have significant wetland components. Pathogens, parasites, …

Intelligent transportation systems

Abstract: In the 1980s, a small group of transportation professionals recognized the impact that the computing and communications revolutions of the Information Age could have on surface transportation. The idea of Intelligent Transportation Systems (ITS) was born. This paper gives a very brief history of ITS, and a short summary of what remains to be done to increase the public acceptance of ITS.

Traffic Volume Time‐Series Analysis According to the Type of Road Use

Abstract: Problems related to highway traffic operation and congestion management can be alleviated with the use of modern intelligent transportation systems (ITSs). Advanced Traveler Information Systems (ATIS) is one of the emerging technologies that will help travelers plan routes and schedules of their trips so as to redistribute the traffic over the highway network. Such redistribution will try to maximize the use of available highway capacity. Collections of real-time data and short-term predictions of traffic volumes are among the critical needs of an ATIS. This article studies characteristics of different traffic volume time series. In particular, time-series analysis is applied to the prediction of daily traffic volumes. The daily traffic volume is estimated by using the previous 13 daily traffic volumes. The study involves a comparison of statistical and neural network techniques for time series analysis. The analysis is applied to different types of road groups according to the trip purpose and trip length distribution. It is hoped that this study will provide a better understanding of various issues involved in the short-term prediction of traffic volumes on different types of highways.

Intelligent Transportation Systems : New Principles and Architectures

Abstract: To serve the needs of the future, transportation systems must undergo a radical transformation, from the centralized paradigm to the asynchronous, distributed paradigm that integrates fast computers and high-performance networks through novel computer algorithms. Intelligent Transportation Systems takes the first step towards meeting that challenge. Focusing on highway and railway systems, the authors stress the need for computer modeling and simulation to help design and validate complex, large-scale systems and the design of new performance metrics to estimate the performance of these systems. They present the basic principles related to travel-related decision making, including coordination, control, and routing.

A framework for an integrative freight market simulation

Abstract: This paper discusses a framework for comprehensive modeling of freight movements that presents opportunities for the development of models able to: (a) jointly consider the flow of both commodities and commercial vehicles; (b) consider commercial vehicles trip chaining, or alternatively trip length distributions (TLD); (c) use logistic information in freight demand modeling; (d) estimate freight origin destination matrices, on the basis of secondary information, such as traffic data from intelligent transportation systems (ITS); (e) enable the study of the impact of real-time traffic control upon commercial vehicle traffic. The concept discussed here entails a bi-level approach in which the top level correspond to the estimation of the provision of service consistent with a Cournot equilibrium, while the bottom level focuses on the construction of tours that satisfy the Cournot solution and the remaining system constraints, in a context of a large scale simulation optimization problem.

Intelligent transportation system architecture for a multi-station shared vehicle system

Abstract: As an innovative transportation paradigm, shared vehicle systems can potentially alleviate traffic congestion, improve air quality, and make surface transportation more efficient. In a multistation configuration however, these systems place an additional burden on both users and system operators. Intelligent transportation technology can play an important role in making these systems user-friendly, easy to manage, and efficient. However, these systems will not necessarily succeed through the application of separate ITS technology bundles. There is an important need to tightly integrate the different types of technology and to develop an effective systems architecture. In this paper, the engineering design and systems architecture for a real-world, intelligent shared electric vehicle system operating on the University of California-Riverside campus are described. This architecture uses innovated techniques for trip registration, intelligent monitoring, and vehicle communication. This system has been set up as a "testbed" to improve our understanding of the operating details of a multistation shared vehicle system, evaluate user segment response, and improve the fidelity of shared vehicle simulation modeling tools.

Spatiotemporal Access Methods

Abstract: Spatiotemporal Database Management Systems (STDBMSs) manage data whose geometry changes over time. There are many applications that create such data, including global change (as in climate or land cover changes), transportation (traffic surveillance data, intelligent transportation systems), social (demographic, health, etc.), and multimedia (animated movies) applications. For simplicity we consider two spatial attributes, the object position and extent, either (or both) of which can change with time. Based on the rate that spatial attributes change, we identify two cases: the discrete and the continuous spatiotemporal environments. We first introduce the basic characteristics and interesting queries for each environment and then present efficient spatiotemporal indexing techniques.

Anticipatory Traffic Forecast Using Multi-Agent Techniques

Abstract: In this contribution, intelligent transportation systems (ITS) and their impact on traffic systems are discussed. Although traffic forecast offers the possibility to rearrange the temporal distribution of traffic patterns, it suffers from a fundamental problem because the reaction of the driver to the forecast is a priori unknown. On the other hand the behaviour of drivers can have a serious impact on the quality of a traffic forecast since it can result in a feedback - an anticipatory forecast is needed. To include such effects we propose a two-layered agent architecture for modelling drivers’ behaviour in more detail. The layers distinguish different tasks of road users.

Estimation and Application of Dynamic Speed-Density Relations by Using Transfer Function Models

Abstract: Deployment of intelligent transportation systems (ITS) and availability of a vast amount of online data are opening new opportunities for researchers and practitioners. Many of the previously established methods and applications must be revisited in light of the availability of real-time data. Traffic flow models, particularly speed-density relations, lie at the core of a wide range of applications in almost all areas of traffic engineering and control. In simulation applications and continuum traffic flow models, first-order models use a steady-state or static speed-density relation, whereas higher-order models, with additional terms and parameters, are usually driven by the deviation of speed from this steady-state value. In calibrating speed-density relations using time series data, the existence of serial correlation and other dynamic effects in the data has largely been ignored in previous studies. In this study, transfer function methods (bivariate time series models) are used to specify and estimate dynamic speed-density relations from typical detector data from an advanced traffic management system control center. First the deviation of speed from an equilibrium static relation is estimated, and later the method is extended to directly estimate speed without explicit specification of an equilibrium speed-density relation. The robustness of the model temporally and spatially is investigated. In all cases considered, the method exhibits good performance and robustness in application. Furthermore, since the method is based on the use of online information, it has the capability of being adaptive and adjusting its parameters online.

Map accuracy and location expression in transportation – reality and prospects

Abstract: We were contracted to test a suite of proposed location messaging standards for the intelligent transportation systems (ITS) industry. We studied six different databases for the County of Santa Barbara, documented types and magnitudes of error, and examined the likely success of the proposed standards. This paper synthesizes the test results and identifies caveats for the user community as well as challenges to academia. We conclude that, first, current messaging proposals are inadequate, and superior methods are required to convey both location and a measure of confidence to the recipient. Second, there is a need to develop methods to correct map data geometrically, so that location is more accurately captured, stored and communicated, particularly in mission critical applications such as emergency servicing. To address this, we have developed methods for comparing maps and adjusting them in real time. Third, there must be standards for centerline map accuracy, that reflect the data models and functions associated with transportation.

Intelligent transportation system data archiving: statistical techniques for determining optimal aggregation widths for inductive loop detector speed data

Abstract: Although most traffic management centers collect intelligent transportation system (ITS) traffic monitoring data from local controllers in 20-s to 30-s intervals, the time intervals for archiving data vary considerably from 1 to 5, 15, or even 60 min. Presented are two statistical techniques that can be used to determine optimal aggregation levels for archiving ITS traffic monitoring data: the cross-validated mean square error and the F-statistic algorithm. Both techniques seek to determine the minimal sufficient statistics necessary to capture the full information contained within a traffic parameter distribution. The statistical techniques were applied to 20-s speed data archived by the TransGuide center in San Antonio, Texas. The optimal aggregation levels obtained by using the two algorithms produced reasonable and intuitive results—both techniques calculated optimal aggregation levels of 60 min or more during periods of low traffic variability. Similarly, both techniques calculated optimal aggregatio...