Research issues in intelligent transportation systems

1、Research Issues in Intelligent Transportation SystemsProf. Lee D. Han, Ph.D.Collaborating ScientistUniversity of Tennessee/Oak Ridge National LabI. IntroductionAfter almost two decades of research, development, and implementation activities in the area of Intelligent Transportation Systems (ITS), re

2、searchers and practitioners have achieved and learned quite a bit through various projects and studies. This knowledge and experience, in turn, points to a range of issues, which need be addressed to keep ITS on its course for success.This paper will take a brief retrospective view of ITS, its succe

3、sses and lessons learned along the way, and a number of challenges and research issues facing the transportation professionals currently. Specific emphasis will then be placed on the needs for integrating dynamic information with GIS and real-time interfacing to ITS users. II. A Brief History of ITS

4、In spite of all the attentions and substantial funding it received in recent years, Intelligent Transportation Systems is by no means a new concept. Scientist and engineers had long envisioned automated vehicle-roadway scenarios as early as 1940s. General Motors Firebirds shown here were a result of

5、 one of such dreams. The automated control on the Impala also gave the public a peek of the automated vehicle control technology of the 21st century. Nevertheless, the development and realization of a successful national ITS system only became possible in the last decade as a result of the commitmen

6、t from government, industry, as well as academia.Parallel to the efforts in Europe and Asia, the United States began its quest for an efficient transportation system in mid 80s. Recognizing the fact that massive road construction projects is not the answer to the ever increasing congestion problem,

7、visionaries called for a smarter approach, which employs and deploys innovative ideas and advanced technologies to better serve the transportation needs of the nation as well as its citizens.Started as a non-profit consortium of government, industry, and university member, Mobility 2000 was the firs

8、t national organization to kick off the nations quest towards ITS. Although, University of Californias PATH (Partners for Advanced Transit and Highways) also started at around the same time in 1986 in the State of California. In the late 80s the term Intelligent Vehicle-Highway Systems, or IVHS, was

9、 used, which was later changed to Intelligent Transportation Systems, or ITS, to better represent the scope of this endeavor. In 1991, IVHS America (later ITS America) replaced Mobility 2000 as the result of a Congress mandate. In the same year, Intermodal Surface Transportation Efficiency Act (ISTE

10、A) was enacted to provide the funding necessary for the subsequent research, development, and early deployment activities in ITS. ISTEA expired in 1997; but a new Transportation Equity Act for the 21st Century (TEA-21) was subsequently enacted to continue this national effort.III. Research Issues an

11、d ChallengesThere is host of issues to be resolved before a national ITS can be realized. The following paragraphs identify some of these issues listed in alphabetical order.Architecture and StandardsOne of the main activities early on was to develop a system architecture for the national ITS. The N

12、ational ITS Architecture, which was developed and revised since the mid-90, provides a common framework for planning, defining, and integrating intelligent transportation systems. It is a mature product that reflects the contributions of a broad cross-section of the ITS community (transportation pra

13、ctitioners, systems engineers, system developers, technology specialists, consultants, etc.) over a five year period. The architecture defines: The functions (e.g., gather traffic information or request a route) that are required for ITS, The physical entities or subsystems where these functions res

14、ide (e.g., the roadside or the vehicle), and The information flows that connect these functions and physical subsystems together into an integrated system.Under the National ITS Architecture, a number of user services were identified and to be provided under various User Service Bundles.User Service

15、 BundleUser ServiceTravel and Transportation Management En-Route Driver Information Route Guidance Traveler Services Information Traffic Control Incident Management Emissions Testing and Mitigation Highway-Rail Intersection Travel Demand Management Pre-Trip Travel Information Ride Matching and Reser

16、vation Demand Management and OperationsPublic Transportation Operations Public Transportation Management En-Route Transit Information Personalized Public Transit Public Travel SecurityElectronic Payment Services Electronic Payment ServicesCommercial Vehicle Operations Commercial Vehicle Electronic C

17、learance Automated Roadside Safety Inspection On-Board Safety Monitoring Commercial Vehicle Administrative Processes Hazardous Material Incident Response Commercial Fleet ManagementEmergency Management Emergency Notification and Personal Security Emergency Vehicle ManagementAdvanced Vehicle Control

18、and Safety Systems Longitudinal Collision Avoidance Lateral Collision Avoidance Intersection Collision Avoidance Vision Enhancement for Crash Avoidance Safety Readiness Pre-Crash Restraint Deployment Automated Highway SystemsCommunicationsThere are numerous entities in a large ITS system, which need

19、 to coordinate with one another through the exchange of real-time information. To facilitate this, a National Transportation Communications for ITS Protocol (NTCIP) was developed. The primary objective of NTCIP is to provide a communications standard that ensures the interoperability and interchange

20、ability of traffic control and ITS devices. The NTCIP is the first protocol for the transportation industry that provides a communications interface between disparate hardware and software products. The NTCIP effort not only seeks to maximize the existing infrastructure, but it also aims to allow fo

21、r flexible expansion in the future, without reliance on specific equipment vendors or customized software.Data and Data QualityMany of the decisions (from long-term planning decisions to real-time operational ones) have to be made based on assessments of the transportation systems in question. These

22、 assessments are often statistics aggregated from field data, which may or may not be accurate. How to ensure data quality, how to recognize data quality deficiencies, and how to make informed decisions with suspicious data are of significant to ITS planning and operation activities.Dynamic Traffic

23、Assignment, DTADTA is one of the more ambitious tasks in ITS. It entails the real-time identification of operational problems, the prediction of near future demands, and the assignment of traffic for systemwide delay reductions. Several basic questions persist in this effort in terms of: How to dete

24、ct incidents? How to estimate response/clearance time?NetworkwideTraffic Simulators How to predict near-term O-D matrix?NetworkwideTraffic Simulations How to select alternative routes/plans? How to make timely routing decisions?Education and TrainingOne of the major challenges to ITS is the readines

25、s of the transportation professionals for the new technologies and new ways of thinking brought upon by the implementation of ITS. It is not uncommon that local and, even, state transportation and traffic personnel dont have the proper educational background to realize the full benefit of ITS.Federa

26、l Highway Administration and ITS America have already begun addressing some of issues by forming proper committees and establishing professional capacity building programs. However, additional work is still much needed.Estimation of BenefitsWhile ITS was billed as a less expensive alternative to new

27、 constructions, it has been difficult to measure the benefits of ITS programs. One of the major efforts under way is the IDAS (ITS Development Analysis System) project, which posed fundamental questions including: What benefit does ITS offer? How are the benefits to be measured? How should benefits

28、be valued? How can the information be used?Funding and Sustainability Issues Many of the early ITS research, development, and deployment projects were funded by USDOT. However, it becomes apparent that it is neither feasible nor reasonable for Federal Government to fund all of ITS projects on contin

29、ued basis. In fact, for certain user services it make sense to transfer the operational responsibility to private sectors once “the ball starts rolling.User services such as commercial vehicle operations (CVO), real-time traffic information, in-vehicle navigation, smart cards and electronic payments

30、, pre-trip planning, and, to certain extent, vehicle control systems already received a wide range of acceptance by public and private sectors. By passing on the technology development responsibility to private sectors and funding responsibility to the end users (travelers, shippers, etc.), ITS will

31、 thrive in a free market with minimum dependency on the government.GISITS requires a large amount of information and, in turn, generates a large amount of information. The maturing GIS-based interface becomes a convenient but, nevertheless, powerful tool for information display and storage. Further

32、discussion on GIS and ITS will be discussed in the Session IV.Human FactorsOne of the under-appreciated issues in ITS early on was human factors. To address this lack of understanding of human factors in ITS, tens of millions dollars have since been designated for the research in the development of

33、driving simulators. On the other hand, additional research efforts are still lacking on the safety concerns with the use of in-vehicle navigation and warning systems given that the multitude of information items to be displayed on dashboard-mounted units are often too compact for real-time viewing,

34、manual selection, and decision making.Institutional IssuesEven if all other technological and funding issues were properly addressed, the findings of many early deployment projects indicated that institutional issues are among the most challenging tasks for endeavors such as ITS. The endless questio

35、ns of “who owns what? “who pays for what? “who is in charge when what happens? “who gets the due credit? can easily become the sticking point for any multi-agency collaborations. A recent ITS deloyment effort in a tri-city area involved 17 agencies and companies trying to implement ITS in a small ur

36、ban area. Misunderstanding and individual interests can defeat the glory of all enabling technologies.Keeping Sight on Goals & ObjectivesAs ITS funds become available and ITS projects become trendy, many metropolitan areas seek to take advantage of ITS fund to fulfill local economics development or

37、construction needs. One example is using HOV (high-occupancy vehicle) lane as ITS strategy for funding. The other is using sensor technology testing as objectives to get funding for parking garages. Not only these projects wasted valuable ITS funding sources, but the subject agencies also lost sight

38、 on the goals and objectives of ITS.Marketing and Market Penetration IssuesTo make ITS work, it has to be widely accepted, if not embraced, by the end users, the public. Certain applications, such as ATMS (advanced traffic management system) and DTA (dynamic traffic assignment) require certain perce

39、ntage of market penetration to function. Other applications, such as electronic toll and in-vehicle navigation, need a minimum number of subscribers to break even. For such ITS user services to become free of “subsidies, marketing and market penetration are of high priority.Migration IssuesIn the pr

40、ogress towards a fully functional and fully deployed ITS infrastructure and transportation system, it is important that the migration of technology stages is seamless. That is, new technologies should function properly and safely on existing roadways, and vice versa.Modeling/SimulationsMany of the t

41、echnologies and scenarios can not be tested easily in the field due to safety, monetary, and technological constraints. To this end, modeling and simulation become useful alternatives. These tools are available or are under development on both infrastructure and vehicle sides. The operational as wel

42、l as safety concerns can be thus modeled.Origin-Destination (Demand) EstimationsAs was highlighted in the DTA issues, it is of crucial importance to acquire the real-time demand information in an ITS network. This means not only the origins and destinations of the trips but also the time-variant flo

43、w rates. Such a demanding need is a quantum leap from the OD matrix used in the past for transportation planning purposes. Researchers are using mathematical, heuristic, statistical, as well as vehicle tracking approaches to address this issue with mixed success.A recent study conducted by the autho

44、r using LPR (license plate reader) technology to capture and track vehicles in real-time showed some promising results. The research team was able to derive real-time OD table on limited bases. Additional study is needed however.Operation and Maintenance IssuesMany of the ITS deployment projects foc

45、us mainly on the initial capital investment in technology, equipment, etc. However, ITS, arguably, may demand much higher operation and maintenance attentions from agencies with due jurisdiction. This is because ITS has a much higher dependency on the proper operation of electricity and communicatio

46、n systems. The commitment and vision of these agencies are very important to the long-term success of ITS.SafetyWhile ITS seeks to address some of the safety issues with technologies such as in-vehicle warning systems, secondary safety concerns may surface as a result. It is widely studied and under

47、stood that driver inattention is a leading cause of all fatal crashes. Compounded with other complicated driving tasks, additional information displayed on small screens with tiny buttons could further escalate the hazard of driving. If the use of cellular phone is said to have similarly adverse eff

48、ects on driving as DUI (driving under influence) does, a case could be made that these little navigation gadgets may also have intoxicating effects on drivers.In addition, certain user services such as automated highway systems (AHS) or intelligent cruise control (ICC) a lesser version of AHS, may b

49、e causes for new safety concerns. The potential catastrophic effect resultant from the failure of such systems should be thoroughly investigated.There are many safety factors knowingly or unknowingly built into traditional highway system. Advanced technologies in ITS dont necessarily negate the need

50、s for them.SecurityOnce deployed, ITS systems may become vulnerable to security concerns in more than one ways. Because of the heavy reliance on electronic communication networks, ITS management and control centers can be compromised due to software “bugs, computer viruses, and malicious attack of “

51、cyber terrorists. These issues are appreciated by the researchers to certain extent but often not addressed properly.In addition, for systems such as AHS, which relies on high precision and coordinated executions, physical sabotages can cause catastrophic results resembled only by “train wreck. How

52、to discourage or fend off saboteurs and maintain system integrity and fail-safe operation at all time is germane to the public acceptance and future realization of such ambitious endeavors.SensorsThe intelligence in an Intelligent Transportation System comes partly from knowing the real-time network

53、wide operational condition, which relies heavily on the surveillance and monitoring technologies. To this end, enabling sensor technology and its proper TechnologyAdvantagesDisadvantagesUltrasonic Compact size, ease of installation May be sensitive to temperature and air turbulence Microwave Doppler

54、 Good in inclement weather Directly measures vehicle speed Cannot detect stopped vehicles or vehicles moving less than approximately 5 mph Microwave True Presence Good in inclement weather Detects stopped vehicles Operates in side-looking mode Requires narrow beam antenna to confine footprint to sin

55、gle lane in forward-looking mode Passive (Receive Only) Infrared Greater viewing distance in fog than with visible wavelength sensors Potential degradation by heavy rain and heavy snow Active (Transmit and Receive) Infrared Greater viewing distance in fog than with visible wavelength sensors Directl

56、y measures vehicle speed Potential degradation by obscurants in atmosphere and by inclement weather Visible Spectrum Video Image Processor Provides data for traffic management and imagery for incident management Single camera and processor can serve multiple lanes Rich array of traffic data provided

57、 Potential degradation by inclement weather Large vehicles can obscure smaller vehicles Shadows, reflections from wet pavement, and day/night transitions can result in missed or false detections deployment is of crucial importance. There is an array of sensors based on radar, acoustic, microwave, la

58、ser, video images, etc. technologies, which do perform well, to various extents, in mimicking the traditional inductive loops. Yet each technology also exhibits limitations, if not deficiencies, in certain conditions.In addition, the placement of sensors and sampling rate of the incoming data should

59、 be carefully studied so that minimum amount of resources is needed for maximum amount of surveillance coverage.DetectorUpdate IntervalCountLaneOccupancySpeedVehicleTypeWhelen TDN-30 & TDW-10 Doppler Detectorsper vehicleElectronic Integrated Systems RTMS-X1 True Presence Microwave Radar 10 seconds t

60、o10 minutesaEconolite AUTOSCOPE 2003 VIPc10 sec to 1 hourComputer Recognition Systems Traffic Analysis System VIP 1 minuteTraficon CCATS -VIP 25 secondsSumitomo IDET-100 VIPper vehicleEVA 2000 VIPper vehicleGrumman Infrared VIP1 secondIV. ITS and GIS A Natural FitThe previous section highlighted a n