Showing papers in "PATH research report in 2001"

Geographical routing using partial information for wireless ad hoc networks

Abstract: This paper presents an algorithm for routing in wireless and ad hoc networks using information regarding the geographic location of the nodes. The algorithm, which is a new type of distributed, adaptive and asynchronous algorithm, is known as a geographical routing algorithm (GRA). The authors describe the GRA, and discuss it in relation to other routing algorithms in the literature. A system model and a problem statement are presented. Issues related to position information inaccuracy and inconsistency, and mobility are discussed, along with simulation results.

Evaluation of On-ramp Control Algorithms

Abstract: A freeway corridor consists of the freeway and its entrance/exit ramps, the cross streets, and adjacent parallel arterial streets. It is designed to provide a generally high level of service (LOS) to users and communities. However, many corridors in the country are congested, with the worst congestion problems usually arising during two peak periods, the morning and evening commute. There are two types of traffic congestion: recurrent and nonrecurrent. Recurrent congestion are due to excessive peak demands and nonrecurrent congestion are due to capacity reduction caused by events such as accidents. The control of a traffic corridor, including freeway system control and arterial street system control, can improve traffic flow and has been demonstrated as an effective mean to increase LOS of a corridor system during peak periods. Ramp metering has been considered a very important component of corridor traffic control. There exists a large number of ramp metering schemes in literature. While some of them were implemented in the real world, most of these algorithms are still awaiting further assessment. This report focuses on the most popular algorithms in terms of their usage.

Mixed Manual/Semi-Automated Traffic: A Macroscopic Analysis

Abstract: The use of advanced technologies and intelligence in vehicles and infrastructure could make the current highway transportation system much more efficient. Semi-automated vehicles with the capability of automatically following a vehicle in front as long as it is in the same lane and in the vicinity of the forward looking ranging sensor are expected to be deployed in the near future. Their penetration into the current manual traffic will give rise to mixed manual/semi-automated traffic. In this paper, we analyze the fundamental flow-density curve for mixed traffic using flow-density curves for 100% manual and 100% semi-automated traffic. Assuming that semi-automated vehicles use a time headway smaller than today's manual traffic average due to the use of sensors and actuators, we have shown using the flow-density diagram that the traffic flow rate will increase in mixed traffic. We have also shown that the flow-density curve for mixed traffic is restricted between the flow-density curves for 100% manual and 100% semi-automated traffic. We have presented in a graphical way that the presence of semi-automated vehicles in mixed traffic propagates a shock wave faster than in manual traffic. We have demonstrated that the presence of semi-automated vehicles does not change the total travel time of vehicles in mixed traffic. Though we observed that with 50% semi-automated vehicles a vehicle travels 10.6% more distance than a vehicle in manual traffic for the same time horizon and starting at approximately the same position, this increase is marginal and is within the modeling error. Lastly, we have shown that when shock waves on the highway produce stop-and-go traffic, the average delay experienced by vehicles at standstill is lower in mixed traffic than in manual traffic, while the average number of vehicles at standstill remains unchanged.

Wireless Token Ring Protocol

Abstract: The Wireless Token Ring Protocol (WTRP) is a medium access control protocol for wireless networks in Intelligent Transportation Systems. It supports quality of service in terms of bounded latency and reserved bandwidth. WTRP is efficient in the sense that it reduces the number of retransmissions due to collisions. It is fair in the sense that each station takes a turn to transmit and is forced to give up the right to transmit after transmitting for a specified amount of time. It is a distributed protocol that supports many topologies since not all stations need to be connected to each other or to a central station. It can be used with an admission control agent for bandwidth or latency reservations. WTRP is robust against single node failure. WTRP is designed to recover gracefully from multiple simultaneous faults. It has applications to inter-access point coordination in ITS DSRC, and safety-critical vehicle-to-vehicle networking.

Emergency Vehicle Maneuvers and Control Laws for Automated Highway Systems

Abstract: In this report control laws and maneuvers for high priority emergency vehicle transit on automated highways are presented. The work presented is specifically designed for use with the Partners for Automated Transit and Highways (PATH) hierarchical control architecture. The types of control laws that are needed for the different hierarchical layers are examined, and specific maneuvers for the coordination and link layers are presented. Simulations using SmartCAP (a mesoscopic traffic simulator) and SmartAHS (a microscopic traffic simulator) demonstrate the maneuvers' functionality.

Optimized Vehicle Control/Communication Interaction in an Automated Highway System

Abstract: One of the main goals of an Automated Highway System environment is to increase the throughput of vehicles traveling on the highway. By moving vehicles in a platoon (a group of tightly spaced vehicles), the traffic flow capacity can be greatly increased. The control law developed for vehicles to safely travel in a platoon is dependent on the lead and preceding vehicle's velocity and acceleration profiles. This information guarantees string stability (i.e. spacing errors between vehicles do not increase down the chain of vehicles). These profiles are transmitted to the vehicle via wireless communication. Unfortunately, a perfect wireless communication does not exist. In this paper, the effects of various communication delays on string stability will be analyzed. The concept of platooning in an Automated Highway System (AHS) allows a group of vehicles to share information across a wireless local area network (LAN). This sharing of information allows vehicles belonging to the same platoon to maintain a smaller inter-vehicular spacing that would otherwise be possible. Of course, once these platoon/LANs exist on the AHS, a method must exist to add vehicles to a platoon and also to remove vehicles from a platoon. This report also develops handshaking protocols that allow the LANs associated with each platoon to reconfigure themselves in response to any physical changes to the composition of the platoon. Since the LANs operate over a wireless communication system, these protocols are designed to be robust towards packet losses, as well as satisfying certain safety and liveness conditions.

Development and Performance Evaluation of AVCSS Deployment Sequences to Advance from Today's Driving Environment to Full Automation

Abstract: This report presents the findings of its investigation into deployment sequences to better understand the paths that could be taken from today's driving environment to vehicle-highway automation. One of the most vexing problems has always been that of determining how to advance from the present-day manually-controlled vehicles to the future fully automated vehicles. Considerable research attention has been devoted to defining the architecture and operating protocols, as well as the technology, of automated highway systems. Rather less attention has been devoted to defining the steps by which we can get there. Initially, targets of opportunity were identified for accelerating progress toward highway automation, taking account of the operational constraints. Next, after reviewing existing literature on automated highway systems deployment, a set of principles to govern the design of deployment strategies is suggested followed by proposed deployment sequences for automated highway systems, beginning with adaptive cruise control and then adding elements of vehicle-vehicle cooperation and lane protection to build toward automated highway systems capabilities within constraints of technological, human factors and economic feasibility. A general deployment staging sequence is then presented along with example deployment "roadmaps" shown for transit buses, heavy trucks and light-duty passenger vehicles. Finally, we discuss the findings of our modeling and evaluation work for the beginning stages of a specific deployment sequence for light-duty passenger vehicles in the setting of a single highway lane. This sequence incorporates the use of cooperative adaptive cruise control along with conventional or autonomous adaptive cruise control and manual-driven vehicles. The evaluation assesses the impact of each of these three operational driving modes on traffic flow dynamics and highway capacity as well as of increasing proportions of both autonomous and cooperative adaptive cruise control vehicles relative to manually driven vehicles. Such effects are difficult to estimate from field tests on highways because of their necessarily low market penetration of these vehicles. Our approach uses Monte Carlo simulations based on detailed modeling work to estimate the quantitative effects of varying proportions of vehicle control types on lane capacity and on queue lengths and wait times at on-ramps.

Use of Los Angeles Freeway Service Patrol Vehicles as Probe Vehicles

Abstract: This research examines the feasibility of using existing freeway service patrol (FSP) trucks as probe vehicles for measuring the level of service on Los Angeles freeways. Operational or institutional constraints that might limit the use of the probe vehicles are identified. Possible improvements to loop detector data by cominging it with prove vehicle data are also identified. The research also looks at potential new infrastructure requirements for processing probe vehicle information.

Human Driver Model for SmartAHS

Abstract: PATH AVCSS researches have been traditionally oriented toward automatic vehicle design. Recently, the field of investigation has been extended from Automated Highway System (AHS) to assistance driving systems. One of the tools built at PATH for automatic system design and assessment is SmartAHS. SmartAHS is a micro-simulation tool dedicated to the simulation of automatic vehicles and has shown to be very useful for fully automatic system simulation. These simulations permit researchers to evaluate the impact of such system on throughput improvement. In order to apply the same method to the design of partially automated systems, it is necessary to develop a human driver component for this simulation tool. This component needs to allow the comparison of human driving characteristics versus automated vehicles in the long term, but first, it has to permit the production, for simulation purposes, of a realistic human driving behavior.The goal of the modeling effort presented here is twofold. On one hand, there is an objective to design and evaluate AVCSS at a driver level (respective of human processing constraints), which imply a consideration of the cognitive processes involved while driving. On the other hand, there is also a goal to integrate of the model to a micro-simulation tool, for evaluation of AVCSS at traffic level, and more specifically in terms of throughput evolution. This second goal implies the consideration of vehicle modelsand control of the vehicle. SmartAHS mainly consists of automatically or semi-automatically controlled vehicles. This is why this component is called human driver model (as opposed to automated or semi-automated vehicles). The method preferred for the realization of this model is a capitalization of these various approaches by the application of a driver cognitive model, COSMODRIVE (COgnitive Simulation MOdel of the DRIVEr) (Bellet, 1998). This model conceptual framework is a skeleton around which can be organized the relevant aspects of the different approaches for the purpose of driver modeling. The general architecture of this model will be presented first, with a detailed description of the modules content and exchanges. In Section 2, the implemented modules and procedure of implementation will be described. The third section will be the description of the simulation realized with the model, for both normal driving and emergency case. Finally, this report will conclude with the description of a calibration procedure for part of the model.

Coordinating Automated Vehicles via Communication

Abstract: This dissertation addresses the coordination of automated vehicles in an Auto- mated Highway System (AHS). Tra c in an AHS is organized as tightly spaced platoons to increase road capacity and safety. Vehicles in AHS are automated and their safe interaction is the subject of this research. This dissertation discusses issues in the design and imple- mentation of a controller for automated vehicles that coordinates the interaction between vehicles. We rst de ne a formalism for safe interaction of automated vehicles and then design a controller algorithm for an individual vehicle that guarantees such safe interaction. The algorithm for the vehicle controller requires real-time information about the relative positions and planned actions of its neighboring vehicles. Therefore, a communication struc- ture is needed to provide this information. We propose a communication structure of local and wide area networks, LANs and WANs, that allows automated vehicles to exchange this information. We also explain communication address resolution in the context of AHS and propose address resolution schemes for one-lane and multi-lane AHS. The scheme for a multi-lane AHS is space-time division multiple access (STDMA) which is an innovative solution to control multiple user access to the communication channel. Finally, we present a vehicle positioning system by using spread spectrum magnetic signals which is used in STDMA communication and coordination control.

Integrating a Comprehensive Modal Emissions Model into ATMIS Transportation Modeling Frameworks

Abstract: Intelligent Transportation Systems (ITS) have generated considerable enthusiasm in the transportation community as a potential means to improve roadway safety, reduce congestion, enhance the mobility of people and goods, and reduce energy consumption and vehicle emissions. In order to estimate these potential benefits, new and improved analytical techniques and simulation models are being developed for ITS. In terms of environmental effects, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) has developed a comprehensive modal emissions and energy consumption (CME/EC) model that can be directly used for ITS evaluation. In this project, an examination was performed on the key interface issues between the detailed CME/EC model and other ITS simulation models and analytical techniques developed within the California PATH program. Methodologies for integrating various ITS transportation models/data sets with the CME/EC model were established. These integration issues are not trivial; many ITS simulation models and analytical techniques inherently have different levels of aggregation and detail (e.g., both in time and across various vehicle fleets). Much of the work performed focused on integrating the CME/EC model with PARAMICS. PARAMICS is used throughout CALTRANS and the PATH program for various ITS studies. After successfully completing this integration, two case studies were carried out using this PARAMICS/CME-EC tool. The first case study examined the emissions impact of HOT lanes along the SR-91 corridor in Southern California. The other case study examined the emissions impact associated redesignating uphill lanes on I-60 near Riverside, California. By completing these case studies, the integrated transportation/emissions model was thoroughly debugged. These case studies can serve as examples as how to apply this new tool for creating microscale emission inventories. In this report, background material is first provided on the Comprehensive Modal Emissions/Energy Consumption (CME/EC) model and ITS traffic simulation modeling efforts in the California PATH program. This is followed by a description of the integration methodology between CME/EC and PARAMICS. In the last part of the report, two separate case studies are described, where analyses with the integrated models were carried out.

Robust Lateral Control of Heavy Duty Vehicles

Abstract: This report focuses on the robust lateral control of heavy vehicles for automated highway systems. The report first presents a coordinated steering and differential braking controller. An analogy is then made between a vehicle lateral control system and a mechanical system with the coulomb friction. Two feedforward compensators, combined with linear robust controller, are proposed for improving tracking performance of the linear feedback control systems. Through experiments, it is shown that a linear controller with feedforward compensation lifts the performance upper limit of the linear feedback control system and improves system performance. The report also presents solutions to the heavy vehicle autonomous following lateral control problem using a laser scanning radar unit. Using simulation results, it is shown that using the same reference point on the preceding vehicle as the regulation point on the following vehicle is important.

Institutional Aspects of Bus Rapid Transit Operation

Abstract: This report presents the findings of its investigation of institutional aspects of bus rapid transit (BRT) through both a macroscopic examination, a survey of members of the U.S. Bus Rapid Transit Consortium and several Canadian transit properties, and a more focused site-specific examination of three California BRT systems. The macroscopic examination resulted from a literature review, project team brainstorming meetings, and input from the Federal Transit Administration. Several dozen issues were identified and were grouped into nine categories that formed the basis of the survey: intergovernmental and inter-organizational; intra-transit property; political; public relations and marketing; funding and finance; labor; safety and liability; planning and land use; and the physical environment. The survey was administered to members of the U.S. Bus Rapid Transit Consortium and several Canadian BRT systems. Survey responses were analyzed to discern those issues that were deemed to be the most important and most difficult to resolve overall and with respect to distinct BRT system operational settings, respondents' organizational affiliation, and professional experience. In addition, those issues for whom the respondents were most unfamiliar as well as new issues identified by respondents were also examined. Recommendations for resolving the issues based on respondents' views are also presented. Finally, a closer examination of the findings from the perspective of the three California BRT systems was conducted to assess the state's BRT systems. Overall, the following issues were deemed the most important and most difficult to resolve: Local and business community opposition to the removal of/restrictions on parking spaces for BRT use; Availability and acquisition of right-of-way or physical space; Integration of multiple priorities, objectives, and agendas; Concerns over long term funding commitments to BRT; Impacts of BRT on roadway operations; Finding political champions to support BRT; Gaining community support for transit-oriented development; Educating the public on BRT, and managing perceptions and expectations. Valuable insight has been gained into the institutional issues of bus rapid transit that are actually experienced. Key Words: bus rapid transit, institutional issues, survey

Compression Braking for Longitudinal Control of Commercial Heavy Vehicles

Abstract: This paper uses Postscript Type 3 fonts. Although reading it on the screen is difficult it will print out just fine.

Carlink II: Research Approach and Early Findings

Abstract: CarLink II is a commuter-based carsharing pilot project administered by the Institute of Transportation Studies at the University of California, Davis (ITS-Davis) in conjunction with Caltrans, American Honda Motor Company, and Caltrain. Partners for Advanced Transit and Highways (PATH) researchers are conducting the evaluation. Launched in Summer 2001, CarLink II continues the investigation of commuter-based carsharing that was originally explored in the 1998 CarLink longitudinal survey (Shaheen, 1999) and the 1999 CarLink I field test (Shaheen et al., 2000). Lessons learned during the CarLink I field test helped guide the project team’s design of the CarLink II project, resulting in several differences and improvements. The original CarLink I field test ran from January to November, 1999 and featured 54 individuals sharing 12 natural gas powered Honda Civics. The vehicles were based at the Bay Area Rapid Transit (BART) station in Dublin/Pleasanton, the eastern terminus of the BART system. The shared cars were equipped with smart technologies including tracking, communication, and reservation systems to facilitate access and logistics. The model incorporated transit-based carsharing for traditional and reverse commute travel patterns, as well as a day-use fleet application, tested at a major employment centerthe Lawrence Livermore National Laboratory (LLNL).

Integration of GPS/INS and Magnetic Markers for Advanced Vehicle Control

Abstract: CALIFORNIA PATH PROGRAM INSTITUTE OF TRANSPORTATION STUDIES UNIVERSITY OF CALIFORNIA, BERKELEY Integration of GPS/INS and Magnetic Markers for Advanced Vehicle Control Jay Farrell, Matthew Barth University of California, Riverside California P A T H Research Report UCB-ITS-PRR-2001-38 This work was performed as part of the California PATH Program of the University of California, in cooperation with the State of California Business, Transportation, and Housing Agency, Department of Transportation; and the United States Department of Transportation, Federal Highway Administration. The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the State of California. This report does not constitute a standard, specification, or regulation. Final Report for TO 4213 December 2001 ISSN 1055-1425 CALIFORNIA PARTNERS FOR ADVANCED TRANSIT AND HIGHWAYS

Completing the Circle: Using Archived Operations Data to Better Link Decisions to Performance

Abstract: In this report, the authors summarize current practices in using archived operations data to better link decisions to transportation system performance. Investigations took place regarding data archiving and performance monitoring activities in selected locations with focus on the use of performance measures in improving operations. The authors first provide an overview of a traffic performance measures system and its components, followed by a summary of the major findings for each system component. Three primary conclusions are reached: 1) better utilization of archived data will require time and experimentation with data; 2) archived traffic data should be used to improved traffic management center (TMC) performance; and, 3) assignment of responsibility and adequate funding are the keys to effective data archives.

ATIS- Alternative Revenue Approaches

Abstract: As part of a continuing research on Advanced Traveler Information Systems (ATIS), this report presents an institutional analysis of alternative approaches to sustaining publicly supported ATIS. The fifteen largest metropolitan regions in the US and the private sector efforts were investigated through a literature review and in-person and telephone interviews. The study goals were to investigate alternative revenue approaches to achieve a self sustaining ATIS, identify institutional barriers to achieving self-sustainability, and develop a framework of assumptions. Two public sector approaches are; publicly centered with ATIS principally serving public transportation management goals and ATIS market growth with an emphasis on building a self-sustaining ATIS based on products that will sell, using existing, tested technology. The private sector initiatives are dependent on commercialization: investments to set up regional ATIS functions and investment on a national infrastructure. Institutional barriers impeding sustainability include: need for continuity of leadership, inter-jurisdictirional disputes, retaining technical expertise, maintaining public-private partnerships, and deploying interoperability standards. Keywords: Advanced Traveler Information Systems, institutional barriers, revenue models

Section-Related Measures of Traffic System Performance: Prototype Field Implementation

Abstract: In this project (MOU 336),an initial phase of a field implementation was accomplished of the results of a previous research project (MOU 224),in which a vehicle reidentification algorithm based on loop signature analysis was developed using freeway traffic data.This algorithm was extended to non-freeway cases, initially using a section of 2-lane major arterial in cooperation with the City of Irvine,California.The technique was enhanced to address problems such as irregularities in vehicle signatures associated with trucks,tail-gating vehicles and erroneous counting of vehicles,with the objective of obtaining 100% correct counts at each station.The enhanced algorithm was also applied to a major specially instrumented signalized intersection in Irvine,California to demonstrate acquisition of data for real-time congestion monitoring,incident detection and level of service measurement.The initial application was for through vehicles on one approach.In order to achieve more reliable vehicle reidentification results,additional routines for vehicle movement filtering at the downstream station were applied.Reidentification results based on an initial dataset showed an encouraging matching result of 84.07%overall,for individual vehicles.Speed estimation from a single loop signature was one of the applications investigated in detail. For several study sites,the vehicle reidentification matching rates,using speed estimated from a single loop,were only slightly lower than for double loops.In another detailed application (using freeway data collected in previous PATH project MOU 224),vehicle classification using a Backpropagation Neural Network showed an 80 %classification rate overall for all vehicle types.Heuristic approaches to vehicle classification also demonstrated good results.

Fault Detection and Handling for Longitudinal Control

Abstract: The purpose of this project is to extend and integrate existing results on fault diagnostics and fault management for passenger vehicles used in automated highway systems (AHS). These re-sults have been combined to form a fault diagnostic and management system for the longitudinal control system of the automated vehicles which has a heirarchical framework that complements the established PATH control system. Furthermore, the fault diagnostic module effectively mon-itors all of the sensors and actuators required for longitudinal control, while the fault handling module corrects for any detected faults via controller reconfiguration and degraded modes of op-eration. Simulations using the SHIFT programming language are presented to demonstrate the performance of the fault diagnostic and management system for different fault scenarios. Limited experimental results are also provided to show the initial stages of real-time implementation.

Documentation of the irvine integrated corridor freeway ramp metering and arterial adaptive control field operational test

Abstract: A systematic evaluation of the performance and effectiveness of a Field Operational Test (FOT) of an integrated corridor-level adaptive control system was attempted from fall 1994 through spring 1999 in the City of Irvine, California. The FOT was conducted by a consortium consisting of the California Department of Transportation (Caltrans), the City of Irvine, and two private sector consultants, National Engineering Technologies, Inc. (NET) and Farradyne Systems, Inc. (FSI, now PB/FSI), with the City of Irvine as the lead agency. The FOT was cost-share funded by the Federal Highway Administration as part of the Intelligent Vehicle Highway System Field Operational Test Program. The FOT involves an integrated Advanced Transportation Management System (ATMS) which extends the capabilities of existing traffic management systems in the City of Irvine and in Caltrans District 12 (D12). The evaluation originally entailed both a technical performance assessment and a comprehensive institutional analysis. This documentation of the Irvine Field Operation Test does not constitute a formal evaluation due to the failure of any of the planned technologies to be successfully implemented in the field. Due to the extended time frame associated with the project and the significant range of technical and institutional issues associated with the development and eventual failure of the FOT, a summary of project development, institutional barriers, and technical failures is provided.

Brake System Modeling and Control

Abstract: CALIFORNIA PATH PROGRAM INSTITUTE OF TRANSPORTATION STUDIES UNIVERSITY OF CALIFORNIA, BERKELEY Brake System Modeling and Control J.K Hedrick, M. Uchanski University of California, Berkeley California PATH Research Report UCB-ITS-PRR-2001-25 This work was performed as part of the California PATH Program of the University of California, in cooperation with the State of California Business, Transportation, and Housing Agency, Department of Transportation; and the United States Department of Transportation, Federal Highway Administration. The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the State of California. This report does not constitute a standard, specification, or regulation. Report for MOU 308 September 2001 ISSN 1055-1425 CALIFORNIA PARTNERS FOR ADVANCED TRANSIT AND HIGHWAYS

Assessing Opportunities for Intelligent Transportation Systems in California's Passenger Intermodal Operations and Services

Abstract: This report presents the findings of its investigation into intermodal passenger transfer facilities' operations and services in urban areas of California and the opportunities for how the application of intelligent transportation systems may enhance such operations and services. The project was based initially on a macroscopic assessment of intermodal passenger transfer facility operations and services primarily by means of a review of the literature followed by a three-tier analysis through site visits, institutional aspects, and user views and opinions. Institutional aspects were captured by means of a survey administered to representatives from transit service providers sharing three intermodal passenger transfer facilities: a BART station and a Caltrain station in the San Francisco Bay area and the Santa Fe Depot in San Diego where buses, commuter rail lines, and the San Diego Trolley come together. User views were captured by means of a survey administered to users of the BART station. From the literature, numerous barriers associated with the successful implementation of passenger intermodal operations and services were identified along with strategies to overcome these barriers. From the site visits, differences across public transit modes, i.e., between rail and bus, across different urban regions, were identified in the level of use of intelligent transportation system technologies and the level of overall coordination among transit service providers sharing a facility. The institutional survey reveal interesting facts regarding how agencies collect and share data and cooperate at the intermodal facilities under investigation as well how facilities are managed and the degree to which agencies use or are planning to use intelligent transportation systems technologies. The user survey was in the San Francisco Bay Area, with findings revealing user insight into how such a facility operates and the services it provides including information on user behavior, the transfer process, user history for this facility, a rating of the facility, and a demographic profile.

Incident Management: Process Analysis and Improvement

Abstract: This report presents the results from a project which examined the processes used for clearing incidents on highway, with focus on highways in the Southern California region. It documents incident clearance process and processes used in clearing specific incidents. It also describes models and simulations for evaluating alternative dispatch processes. The report begins by describing processes used in clearing incidents. Principles for dispatching mobile response units to incidents are then described. The INCISIM incident simulator is discussed, followed by an analysis of individual incidents. Recommendations for response units to improve operations are offered in the conclusion.

New Hardware and Software Design of a Field-Deployable Real-Time Laser-Based Non-Intrusive Detection System for Measurement of True Travel Time on the Highway

Abstract: A new version of a field-deployable real-time laser-based detection system has been developed using new techniques of electronics and optics. The laser-based non-intrusive detection system uses a laser line that is projected onto the ground as a probe. The reflected light is collected and focused into a photodiode array by an optical system. Vehicle presence is detected based on the absence of reflected laser light. By placing two identical laser/sensor pairs at a known distance apart, the speeds of both the front and rear of a vehicle are measured based on the times when each sensor is triggered. The length of each vehicle is determined by using these speed measurements and the residence time of the vehicle under each sensor. A new version field prototype of a detection system for real-time measurement of delineations of moving vehicles for highway testing has been developed based on our previous research on the laboratory prototype of the system. The new version utilizes new techniques in electronics, optics and software. The testing results show that the new system can obtain the accuracy of measurement necessary to distinguish moving vehicles on the highway. It is an important step to approach the final goal of this project, described in the last report as developing a roadway detection system that can be used to gather reliable travel time data non-intrusively. The new system quantitatively proved that the principle of measurement is feasible, instead of qualitatively as did the last version system. Several tests have been done with the field prototype system on the highway. The software for real-time data acquisition, data processing and graphical user interface has been developed in the Windows NT system with RTX real-time extension. In the software, the speed, acceleration, and length of a detected vehicle can be calculated and displayed simultaneously. This document describes the design and implementation of each functional component and software of the new field prototype system. The measurement and calculation of laser power has been performed to ensure that the system is safe to expose to the public during field tests and future operation on the highway.

A token-ring medium-access-control protocol with quality of service guarantees for wireless ad-hoc networks

Abstract: In this report, the authors describe the design and implementation of a wireless token bus protocol for local area networks. The protocol is significant in that it permits the wireless radios to dynamically join and leave the network while still maintaining the quality of service for those remaining in the network. In addition, this version relaxes an earlier version of the protocol which worked only when each wireless radio in the network was within range of every other radio in the network at all times. This report specifies procedures for radios joining and leaving the network, detecting and removing multiple tokens, recovery from node or link failure, and generating unique ring identifiers. A formal proof is provided for the correctness of these procedures.

Development and Testing of Field-Deployable Real-Time Laser-Based Non-Intrusive Detection System for Measurement of True Travel Time on the Highway

Abstract: We have developed a field prototype of a laser-based non-intrusive detection system for real-time measurement of delineations of moving vehicles for highway testing, based on our previous research on the laboratory prototype of the system. The primary goal of this project is to develop a roadway detection system that can be used to gather reliable travel time data non-intrusively. The system uses a laser line that is projected onto the ground as a probe. The reflected light is collected and focused into a photodiode array by an optical system. Vehicle presence is detected based on the absence of reflected laser light. By placing two identical laser/sensor pairs at a known distance apart, the speed of both the front and rear of a vehicle is measured based on the times when each sensor is triggered. The length of each vehicle is determined by using these speed measurements and the residence time of the vehicle under each sensor. We have built a field prototype detection system which is used not only to proof the concept and algorithm of the detection system, but also to test the system in the real traffic environment. Several tests have been done with the field prototype system on the highway, and the test results further verified that the principle of our detection system is technically sound and indicated that the algorithm implemented in the software works in most cases. The software for the real-time data acquisition, data processing and graphic user interface has been developed in a real-time operating system. In the software, the speed, acceleration, and length of a detected vehicle can be calculated and displayed simultaneously. This document describes the design and implementation of each functional component and software of the field prototype system. The measurement and calculation of laser power has been performed to ensure that the system is safe to expose to public during the field tests and future operation on the highway.

Revenue Models for Advanced Traveler Information Systems

Abstract: The paper describes current trends in the traveler information supply system and the prospect for potential markets for advanced traveler information in the United States and Europe. Alternative revenue models are identified that may be able to support the operation of the newly created traveler information centers in the post-field operational test phase. In the past, public agencies have been reluctant to share traffic management responsibilities with the private sector. However, this study found that the current trend is toward a public-private partnership in the form of a franchised or revenue sharing program. In the United States and Europe, many private entrepreneurs are currently involved in beta testing their products and in assessing the business viability of advanced traveler information services. In Japan, several types of in-vehicle devices are already commercially available to the consumer. The market potential for privately offered advanced traveler information services in the United States and Europe is; however, yet to be determined since consumer purchase behavior for traveler information is largely unknown. The study investigated alternative revenue models that could support the operation of the newly created Traveler Information Centers in the post-field operational test phase. The interest was to explore the Traveler Information financing mechanisms for short- and long-term viability in Traveler Information Center operation. Keywords: Revenue Model, Market, Advanced Traveler Information System

Sensor-Friendly Freeways: Investigation of Progressive Roadway Changes to Facilitate Deployment of AHS

Abstract: Intelligent driver assistance systems which utilize in-vehicle forward-looking sensors can be supplemented by vehicle-vehicle and vehicle-highway cooperative elements to comprise a sensor-friendly highway environment that would enhance the operational efficiency, and ultimately, the safety benefits of these systems In our research, we have identified the current limitations of autonomous sensing systems in target/background discrimination with cluttered highways Based upon this, and by limiting ourselves to sensed (and not wireless) systems, we have conceived relatively inexpensive vehicle-highway cooperative systems to allow those limitations to be mitigated Emphasis has been placed on 77 GHz (millimeter wave) automotive radar sensors - a sensor type which is in current use and when improved, will result in improved longitudinal safety products in the near-to-mid term, up through the longer term vision of full vehicle-highway automation In the work reported here, we introduce the concept of sensor-friendly high systems, describe roadside signatures, and using these as bases, discuss our concepting and experiments several cooperative vehicle-highway concepts We describe experiments and results from prototypes of three of the potentially nearest term means to realize a cooperative collision avoidance systems, which we regard as the first step toward sensor-friendly highways 1 We describe three potential systems: Light Emitting Diode Brake Light Messaging, Roadside-Mounted Corner Cubes, and Passive License Plates We believe that while experimental results point toward the need for further proof-of-concept refinements, these systems potentially represent technologically sound cooperative vehicle-roadway components, and that indeed, sensor friendly systems, when put to the test, can eventually translate into significant benefit in terms of lives saved

Traffic Data Measurement and Validation

Abstract: CALIFORNIA PATH PROGRAM INSTITUTE OF TRANSPORTATION STUDIES UNIVERSITY OF CALIFORNIA, BERKELEY Traffic Data Measurement and Validation Benjamin Coifman The Ohio State University California PATH Research Report UCB-ITS-PRR-2001-40 This work was performed as part of the California PATH Program of the University of California, in cooperation with the State of California Business, Transportation, and Housing Agency, Department of Transportation; and the United States Department of Transportation, Federal Highway Administration. The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the State of California. This report does not constitute a standard, specification, or regulation. Final Report for MOU 3000 December 2001 ISSN 1055-1425 CALIFORNIA PARTNERS FOR ADVANCED TRANSIT AND HIGHWAYS