901505

Social and Institutional Considerations inIntelligent Vehicle-Highway Systems

Steven E. UnderwoodThe University of Michigan

Ann Arbor, MI

ABSTRACT

Recent advances in communications and electronics~echnologies pro~se to allow significant improvementsm the overall efficIency. These advances promise toenable real-time adjustments of traffic to current andpredicted.travel conditio~s, more.effective trip planningand real-tlme route selectlon and improvement in overallroad safety. In developing and planning for thesesystems we need to make assessments about how eachof these promises are actually going to payoff. Arethere markets for these systems? What are the likelybarriers to adoption? What policies can be adopted toovercome these barriers? What are the likely impacts ofthese developments? How will social and institutionalconsiderations impinge on these developments? Thispape: presents the resul~ of a Delphi survey of experts'opmlOns on these questlons regarding the futuredevelopment of intelligent vehicle-highway systems(IVHS) in North America

The development of technology is always uncertain.The course of technology development is determined inpart by undefined societal needs, uncertain institutionalsupport, and unexpected technical breakthroughs.However, technology development is also determined inpart by things that are known or things that can beinfluenced. For example, the future of a particulartechnology can be estimated by current market trends,recent developments in related technologies, currentlevels of institutional support, and an assessment of thenation's level of commitment to research anddevelopment in the area. Given that some things areknown, and that others are uncertain, effective planningfor technology development requires an assessment ofcurrent knowledge and intentions as they impinge on thefuture of the technology in question. It requires reducingthe uncertainty wherever possible, understanding thesources of uncertainty where it cannot be influenced, andformulating a common vision for those who are requiredto act. This is the task we face in assessing the future of"intelligent" transportation systems.

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This report presents the results of a survey ofexperts' opinions on the future of intelligent vehicle­highway systems (IVHS) in North America. IVHS areroad transportation systems that use advanced electronicsand communications technologies to integrate theinformation and control functions of the vehicle and thehighway, thereby improving the performance of theintegrated system, subject to the desires of the driverand/or the traffic manager. Not the least of theseopportunities has been the possibility of tapping a largeand receptive market for these benefits. In-vehicle routeguidance systems that provide motorists with informa­tion on the quickest route to their destinations on thebasis of real-time data supplied by a traffic control centerare an example of an integrated IVHS. Advanced vehiclenavigation and information systems, and other IVHSdescribed in this document, are designed to improve theoverall performance of road transportation in a numberof ways, including providing advice to the driver,assisting the driver with the operation of the vehicle,and/or managing the overall flow of traffic. Desiredresults include increased mobility, safer streets, a cleanerenvironment, more effective use of resources, andimproved comfort and convenience, to name a few.

The forecasts for a range of IVHS categories, aslisted below, were produced by the Delphi techniquewhich is a survey method commonly used for elicitingconsensus opinion from a panel of experts. The Delphitechnique is often used for forecasting the developmentof new technologies and policy events that cannot beeffectively modeled through extrapolative methods. Thisparticular application assessed the panel's forecasts ofmarket penetration, and related influencing factors, forselected categories oflVHS. It also addressed theexpected impacts from implementation of these technolo­gies. The survey emphasized advanced driver in­formation systems (ADIS), advanced traffic managementsystems (ATMS) and automated vehicle control systems(AYeS), following the programmatic structure of theUniversity of Michigan (UM) program on IVHS.

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DesignQuestionnaire

SummarizeResponses(statistical)

Figure 1. The Delphi Process

ReviseResponses

Thirty-two experts in automotive transportation,vehicle electronics, and vehicle communicationsparticipated in the survey. These individuals wereaffiliated with organizations represented on the advisoryboard of the UM's research planning project in IVHS,including the "big three" automotive manufacturers, theirsuppliers, electronics and computer companies, highwayusers, several public transportation agencies, and otherorganizations with interests in IVHS. The participantswere asked to assess the rates of market penetration,influencing factors, and expected impacts for each of thefollowing categories of NBS:• Automatic tolls and road pricing

Automatic vehicle location• Automatic vehicle navigation

Motorist informationCooperative route guidanceCollision warningCollision avoidanceSpeed and headway keepingAutomated highwayAutomated guideway

To generate the forecasts, the Delphi administratormailed questionnaries which asked for each of thesesystem categories the future time at which the followinglevels of market penetration would accrue: (1) laboratorytests would be successfully completed, (2) the systemswould be introduced to the market, (3) a majority ofcommercial vehicles would adopt the system, (4) amajority of automobiles would adopt the system, and (5)vehicles would be required by statute to use the system.Participants were also asked to assess the driving forcesfor implementation, the barriers to market penetration,government policy initiatives, and possible sociotechni­cal impacts for each of these technologies. As requiredby the Delphi process, responses to the initial surveywere summarized and returned to the participants forfeedback and possible revision. The participants wereasked to reaffirm or revise their assessments on the basisof this feedback and to respond again. The sequence of

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question, response, summary and feedback ran throughthree cycles before the desired level of consensus wasreached.

Included in this report are chapters describing thecontext for the UM Delphi on IVHS, the methodologyfor conducting the forecast survey, the marketprojections and associated factors for the 10 individualIVHS categories, a comparison of the individual andgrouped projections, cross-category comparisons of thedetermining factors, and a comparison of the UM resultswith other similar Delphi studies.

The primary contributions of this survey were theindividualized forecasts of market penetration and thelistings of influencing factors for each of the tencategories of systems listed above. The listings ofbarriers, driving forces, policy initiatives, and so­ciotechnical impacts were compiled in response to open­ended questions on each of these items. Thus, theprocess was open to new ideas or perspectives offeredby the participants. Many of the ideas and perspectivesconf'mned commonly-held views the future of IVHS, buta number of responses offered new ideas that enhancedunderstanding of the future of NBS, and whencombined with the conventional wisdom on the subject,provided further insight on which to base plans for re­search and development. A brief summary of thesefindings follows.

The survey revealed that the panelists expected thetraffic management systems (i.e., automatic tolls androad pricing) to be the first group of systems to bedeveloped and implemented in North America. Thesewould be followed by driver information systems (i.e.,vehicle location, vehicle navigation, motoristinformation, cooperative route guidance, and collisionwarning) and the vehicle control systems (i.e, collisionavoidance, speed and headway keeping, automatedhighways, automated guideways), roughly in that order.

for transition to new and more advanced technologies,cost to federal and state governments, human factors insystem design, slower traffic, and limited applicability ofthe systems.

What will lead society to adopt these new systems?The panelists addressed this question by identifying andranking a number of driving forces for adoption ofIVHS. These include, in order of the ranking by thepanelists, increasing traffic congestion, desire forimproved safety, motorists' desire for comfort andconvenience, the public's demand for travel informationas they become aware of it, declining cost of technologyand operation, an incremental process towarddevelopment and adoption of advanced systems, thecommuter's preference for highway over rail, the noveltyof the technology, and the promise of shorter trip timesby traveling on designated lanes.

How will the federal, state, and local governments beable to assist in the development and implementation ofIVHS? The responses from our panel included: limit theliability borne by manufacturers and government,establish effective standards, provide federal funding orincentives for research and development, provideDepartment of Transportation leadership andcommitment, provide the necessary public infrastructure,provide federal funding for construction and operation,provide state and local enabling legislation, and dedicatelanes and roadways for priority use by vehicles withcooperative technology.

The list of social impacts is similar to the list ofdriving forces, except that it also includes severalnegative outcomes. The cross-cutting items in order ofrank are: reduced congestion, improved safety, increasedcomfort and convenience for motorist, increased driveracceptance of automated control, increased automobilecommuting, and smoother flow of traffic.

The forecasts by the University of Michigan, theInternational Institute for Applied Systems Analysis(IIASA), and the Federal Highway Administration(FHWA) were relatively consistent in terms of thepattern and sequence of system development. There wassome contrast in the timing of system introduction in theU.S. with the FHWA placing introduction of most sys­tems about 10 years behind the other surveys. Thiscould be explained by the FHWA's exclusive focus onpublic highways, as opposed to exclusively privatesector implementations of the technologies or otherspecial applications and the absence of private sectorexperts on the FHWA panel.

Perhaps the most significant rmding from our surveyis that, given the right conditions, there is likely to be agreat deal of progress made in the development of anintelligent vehicle-highway system in North Americaover the next ten years. As an indication of things tocome, the survey indicates that all of the systems, withthe exception of the automated highway, will beintroduced by the year 2000. This implies significanttechnical and institutional advances between now and theturn of the century. It also assumes significant levels ofgovernment support and cooperation between the publicand private sectors. Given the expected rapid de­velopment, we intend to repeat the Delphi surveyperiodically in the future.

The projections for majority use by automobile were"005 for advanced traffic management, 2015 for;dvanced driver information, and 2035 for automated fvehicle control.

According to our panelists, most of the advanceddriver information systems, with the exception ofcooperative route guidance and collision warning, havealready been introduced to market in North America.cooperative route guidance and collision warning shouldfollow closely behind and be introduced in the year1995. Majority use by automobiles is predicted to occurfor management information systems by the year 2000.Although collision warning has yet to be introduced, itwill follow the motorist information systems to majorityuse by the year 2010. Vehicle navigation, guidance, andlocation systems should be used by a majority of au­tomobiles somewhere between 2015 and 2020.According to our data, the most likely sequence ofimplementation for thes~ systems ~ standa:d auto­mobiles over the next thIrty years IS: motonstinformation, collision warning, guidance and navigation,and vehicle location. Although guidance and navigationsystems are likely to enter the market earlier thancollision warning systems, the latter are expected toovertake the former in the market during this period.

The results demonstrate convincingly that researchand development on automatic vehicle control systemswill have to overcome a number of technical barriersbefore the systems come on line. Research on thesesystem will be required through the year 2000 in order toreach the level of successful laboratory tests. The criticaltopic is system reliability. Human factors research onautomated vehicle control will also be required; we willwant to find out how drivers will respond to systems thattake over the control functions. Similar effort must beapplied to collision warning as a precursor of the ad­vanced control systems.

The only other system that will require extensivetechnical research is cooperative route guidance. Herethe primary questions will fall in the areas of systemarchitecture and integration. Basic improvements intraffic-predictive analysis will also be needed. As withmost of the driver information systems human factorswill be an issue.

The consumers' assessment of the overall value ofIVHS may either act as a barrier or a driving force in theadoption of IVHS. Declining technology costs as aresult of technology process innovations may playalarger role in determining the future of IVHS thaninnovations in the technologies themselves.Assessments of the potential system benefits and costs,product markets, and institutional barriers will also berequired. Applied social research should focus on theseareas.

The principal barriers to implementation of lVHSwere social, economic, and institutional. Only systemreliabIlIty andl1uman factors could be consideredteclimcal barriers. In this summary we will address onlythose forces that cut across a number of system cate­gories. Other system-unique factors are described foreach category in chapter 3. The cross-cutting barriers toimplementation, listed in order of importance as rankedby the panelists, are: cost to the consumer, obtainingtechnical reliability, lack of demand, government andmanufacturer liability risks, possible system inef­fectiveness, setting of appropriate standards, planning

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CROSS-CATEGORY ANALYSIS

. As ~art of the D~lphi exercise we asked the panelists~o Ide.ntIf~ and explam those factors that they consideredm esnmanng the m~ket penetration of the ten categoriesof IVHS. We specIfically asked the panelists to delineatewhat they viewed as (1) the driving forces forimplementat~on, (2) the baniers to market penetration,(3) constructlve government policy initiatives, and (4)the expected sociotechnical impacts from adoption of thesystems. They listed factors for each of the ten IVHScategories.

In order to assess the relative importance of theidentified items for each of the IVHS categories weconstructed rating matrices that presented the rating foreach item across each of the IVHS categories. Therewere four matrices in all, one for each of the generalfactor categories: driving forces, baniers, governmentpolicy initiatives, and sociotechnical impacts.

The matrices were used in two ways. First, theywere scanned to identify those items that were importantto a relatively large cross-section of the IVHS categories.We looked for items that had rankings in a number ofcategories, and then compiled a smaller matrix thatcontained the subset of items that were ranked for at leastthree categories. These items would be interpreted ascross-cutting concerns that were important because theycame into play with a wide range of system types. Forexample, "planning of the transition to a newtechnology" is a banier that was not ranked very high forany of the IVHS categories, but it was ranked for four ofthe near-term systems, and will no doubt be an importantconsideration over the next few years. Items that werepeculiar to one or two system categories, no matter howimportant they would be to those categories, were notentered into this cross-cutting concerns matrix. It turnedout that the cross-cutting concerns were those items thattend to get a lot of attention in the literature and ongoingdiscussions in IVHS.

Second, we looked for items that were veryimportant in one or two categories, but were not to beconsidered cross-cutting concerns. We arbitrarilyselected a ranking of five as the low end cut-off pointThese items would be concerns that may be of greatimportance to a single category, but because it did notapply to a number of categories, might not get as muchattention as some of the cross-cutting concerns. Forexample, one barrier for the automated guideways (AG)concept is that it competes with the automated highway(AH) concept. In fact, aside from cost, this was viewedas the most significant problem for widespread adoptionof AG systems. Nevertheless, however important thisconsideration is to AG advocates, this gets little attentionbecause it is confined to a single system that is notconsidered to come on line, if it ever does, until far intothe next century. Insights from this type of analysiswere included in the discussion of the individual systemsin the previous section.

The remainder of this section will address the cross- .cutting driving forces, baniers, policy initiatives, andimpacts identified from compilation of the integratedIVHS-item matrices.

DRIVING FORCES FOR IMPLEMEN·T ATION. According to our panelists, increasingtraffic congestion, combined with resistance to furtherfreeway construction, is the overriding challenge thatwill spur interest in IVHS technology as a means of

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increasing traffic throughput and decreasing traffic delay.The urban traffic situation provides the leadinginducement for developing and implementing IVHS,being ranked highest in seven of the ten IVHScategories. It was ranked high for all of the categories.This is not surprising, with intolerable levels of trafficcongestion in many of the major cities in the U.S. andforecasts that this situation will only worsen in theforeseeable future, transportation planners and otherpublic officials are under siege to find innovate means ofcombating this ever present antagonist. Motoristsin~atiable desire for time produces an enduring conflictwtth the trend toward increasing urban congestion andprovides the primary motivation for exploring IVHS andotl:Ie~ approaches to efficient travel. Just the prospect ofgammg an advantage over other drivers through bettertraffic information or the right to travel of designatedlanes or guideways may provide some appeal. Realimprovements in travel times could very well translateinto private and commercial sales of IVHS vehiclecomponents, as well as lead to public demand forpublicly sponsored systems. As indicated in a separatecategory, the public is likely to demand access tomotorist information if and when it becomes accessible.

Another serious incentive for investigating anddeveloping IVHS technologies is the pilblic's desire, andthe related mandate of the representative public agencies,for increasing traffic safety on the overburdenedhighway network. Although the expected safety im­provements is not as widespread as that of travel timesavings, the prospect of improvements in highway safetyis nonetheless important, and is a central motivation forgovernmental involvement in IVHS developments.Although increased safety is viewed by our panelistsonly as a possible rationale for developments inadvanced driver information systems, it does become theprimary rationale for advancements in advanced vehiclecontrol systems, with safety being the highest rankeditem for collision waming, collision avoidance, andspeed and headway keeping. This is also part of therationale for mandatory use of these systems whenadequate levels of reliability have been attained.

Driving can be a direct source of fatigue, frustration,and general motorist stress. The driver information andcontrol systems promise to relieve some of this stress byreducing the driver's (1) time in traffic, (2) uncertaintyabout travel conditions and delays, and (3) need to attendto demanding driving tasks. As a result, the panelistsranked motorist comfort and convenience to be a sig­nificant driving force for implementation of most of theinformation and control systems. Again, expectedimprovements in motorist convenience could providesufficient reason for development of in-vehiclecomponents, where the value could be captured by thevehicle owner and the manufacturer.

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Table 1. Cross-cutting Driving Forced for Implementation (l = highest ranking)

Other cross-cutting forces for implementation includedeclining technology and operating costs, commuters'distinct preference for highway over rail transportation,the novelty of the technology itself, and the opportunityto take an initial incremental step into a more advancedintegrated IVHS.

BARRIERS TO MARKET PENETRATION.The cross-cutting barriers appear to be related to theprimary system grouping: advanced traffic managementSystems (ATMS), advanced driver information systems(ADIS), or advanced vehicle control systems (AYeS).

Driving Forces ATRP AV," AVN MI CRG CW CA SHK AH AG

Traffic congestion 1 1 1 1 1 4 2 3 1 1

Desire for improved safety 4 10 4 1 1 1 2 4

Motorist convenience 3 7 5 6 3 2 4

Public's demand for travel infonna- 2 2 ation

Declining technology and operat- a 3 7 9ing cost

Provides an initial step toward de- S 6 asired advanced systems

Commuter's preference of high- 7 9 6way over rail transportation

Novelty of the technology 4 11 5

Prospect for travel on special 11 10 5 4designated lanes and guideways

According to our panel's responses the barriers for ADISappear relatively immediate and pragmatic.Manufacturers will be concerned with the end cost to theconsumer and the prospects for selling at a reasonableprofit The panelists expressed general concern-with endcosts and consumer demand, as indicated by the highrankings of these items in the ADIS categories. Ofsecondary importance they identified public ex­penditures, decisions on standards, technical reliability,and human factors in system design. There was alsosome general concern that these systems would havelimited applicability.

Table 2. Cross-cutting Barriers to Market Penetration (l = highest ranking)

Barriers ATRP AVL AVN MI CRG cw CA SHK AH AG

Cost to the consumer 3 1 1 1 3 S 4 2

Reliability: Design of a trusted 2 8 9 1 1 1 1 5system

Consumer resistance, lack of 1 2 2 10 4 3 3 aacceptance, and low demand

Liability: Manufacturer's and 7 2 2 2 3 4government's willingness toaccept

System effectiveness, getting 3 12 a 4 Sthe desired resuns

Standards (equipment and 6 6 4 5 Sbroadcasting)

Planning for transition to new 12 12 7 5technology

Costs (federal government) 9 7 4 2 9 1

Costs (state governments) 7 9 2 4

Human factors in system de- 15 3 a 5sign

Penalizes user, drivers must 9 6 4travel at slower pace

Limited applicability 10 10 11

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The panelists also expressed the concern thatconsumers might not even want systems that would takeover the driver control functions. At least they expecteda certain amount of resistance to the prospect of driverassistance or complete vehicle control. Even ifconsumers were to accept the technology, manufacturersand service providers may not tap sufficient demand,depending on use restrictions and consumer costs. Thisconcern is reflected in the panel's nearly across-the­board rankings of consumer resistance and consumercost.

Finally, the panelists indicated that the controlsystems might even penalize the driver by requiringdriving at a slower pace. This could also affectconsumer acceptance.

GOVERNMENT POLICY INITIATIVES.The cross-cutting government policy initiatives seem tofallout of the barriers and driving forces as describedabove. There was a high level of consensus among thepanelists that the government would have to takesignificant steps toward limiting the liability of publicand private service providers and manufacturers. Even ifthe technology is effective and affordable, even if itimproves highway traffic safety, it will not come tomarket if the manufacturers are

Table 3. Cross-cutting Government Policy Initiatives (l =highest ranking)

There was an entirely different set of prioritiesconcerning the advanced vehicle control systems(AYCS). The overwhelming concern regarding AyeSwas system reliability. Will the developers be able todesign an affordable and effective system that wouldmeet or even surpass the requirements of the driver?Can they design a "trusted" vehicle-highway system?From a technical perspective these questions address theproblem of fault tolerance. The designers must providereliable computer hardware and software to control thesystem as well as provide for sufficient redundancy ineach system component. Ensuring reliability is a criticaltechnical barrier in most of the control systems. Theimportance of this barrier demonstrated by the highestrankings assigned to reliability in the categories ofcollision waming, collision avoidance, speed andheadway keeping, and automated highway. Of relatedconcern and importance is the institutional response tosystem failures. Who will be held liable for damages asa result of system failure? Settlement of the liabilityissues was the second highest ranking barrier across theAYCS categories.

Government Initiatives ATRP AVL MI CRG AVN Cli CA SHK AH AG

Liability protection (lirrltation) 11 6 2 1 1 1 2 3

Establishing standards 3 6 2 3 5 3 2 2

Federal funding or incentives 8 5 1 5 5 1 1for R&D

DOT leadership, initiative, and 3 9 4 4 4 9 5commitment

Provide the necessary public 5 2 3 6 9infrastructureAppropriating adequate 1 1 4 3 10funding

Local, state, and federal legis- 1 5 10lation to implement

Dedicated lanes and roadways 9 3 8 3(increase benefit to purchaser)

vulnerable to large-scale suits. This is especiallyimportant with the control systems, but also of concernwith the infonnation systems. For example, who will beresponsible for accidents that occur while the motorist isreading the digitized map that was installed in theinstrument panel? As these technologies come closer tomarket the urgency of these questions will increase.According to our panel, expeditious government actionwill be required to attain the expected levels of marketpenetration.

Another role of the government in support of rapidprogress in IVHS is the wise specification and use oftechnical standards to assure requisite levels of horizontaland upward compatibility. Government standards are anecessary catalyst for technology development in diversetechnical areas such as IVHS, but they can also stifledevelopment and provide an easy target for competitivedisputes. Nevertheless, the sentiment of the panel wasthat the government must get involved early in settingstandards for IVHS.

Many of the systems will require roadside~frastructur: and ot~er system elements that may falllOto the publIc domatn. These elements could includeanything from tags on license plates to central computingand.infonnation facilities. Depending on the nature ofthe mfrastructure and the jurisdiction, funding andpro~sion of the public portion of IVHS may take on avanety of fonns. Despite this flexibility and range inarrangements there was general consensus on the panelthat the government would need to provide certaincomponents of selected IVHS.

Other cross-cutting government roles included (1)federal funding of research, development,demonstration, and general implementation andoperation, (2) display of leadership and commitment,along with assistance in planning for IVHS, (3)legislating implementation, and (4) the provision ofdedicated lanes and guideways and an incentive for use.It seems curious that the panel ranked federal funding ofresearch and development as the top initiative for auto-

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malic vehicle navigation systems. One panelist supplied to a great extent with the driving forces for adoption asa representative dissenting remark writing "this presented in Table 1. Most of the expected impacts weretechnology is developed to the point where government positive and would serve as driving forces forfunding is not approriate." Yet, that is where it remained impl~mentationof the systems. An impact that mightafter three rounds of responses to the survey, despite pOSSIbly have a negative consequence is increasedconsiderable dissent on this topic. automobile commuting. While IVHS increases the

SOCIOTECHNICAL IMPACTS. As seen in throughput of the system, travel times may not decreaseTable 4 the expected sociotechnical impacts correspond due to increases in the number of trips and commuters.

Table 4. Cross-cutting Sociotechnical Impacts

Social Impacts ATRP AVL AVN MI CRG CW CA SHK AH AG

Reduced congestion: 1 1 1 1

Improved Safety: 6 6 3 3 2 1 1 2 1

Improved convenience: 2 12 7 2 4 4

Consumer acceptance 10 6 7 5 7

Increased automobile com- 7 3 8muting

Smoother flow of traffic on toll 3 9 3roads

DISCUSSION OF INDIVIDUAL IVHSTECHNOLOGIES

Discussion of the IYHS categories is organized bytheir targeted source of control, with either the roadside,the driver, or the vehicle being the targeted controlconstituent. Three broad categories of IYHS will beused:

• ATMS Advanced traffic managementsystems (roadside control),

• AD IS Advanced driver informationsystems (driver control), and

• AVCS Automated vehicle controlsystems (vehicle control):

These categories were first delineated at the Mobility2000 workshop that addressed scenarios for a nationalagenda in IVHS (Harris & Bridges, 1989). For thepurposes of this paper each broad category encompassesa number of specific system categories. Advanced trafficmanagement systems (ATMS) control traffic throughroadside displays or signals, which may be coordinated,or even optimized, at a central control facility. AlthoughATMS is a well developed field of application andresearch, few of these systems involve significantvehicle-highway interaction; automatic tolls and roadpricing (ATRP), as a subcategory under ATMS, wasmcluded in this study because of the clear linkagebetween vehicle and highway components.. Advanceddriver information systems CADIS) assist strategic andoperational driver control functions through effective in­formation distribution, processing, and display.Included in this category are automatic vehicle location,automatic vehicle navigation, motorist service informa­tlon. cooperative route guidance, and collision warning..,ystems. All of these systems assume driver control of\ chicle operations and routing and advise the driveraccordingly. Vehicle-highway interaction is mediated bythe driver. Finally, automated vehicle control systemstrJJlsfer control from the driver to the vehicle in order to

-"lability 2000 addressed heavy vehicle and commercialoperations as a fourth and separate category. However,commercial issues have been folded into the first threecJtegories.

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simplify the driving task and improve traffic flow.Vehicle electronics that were strictly autonomous wereexcluded from consideration. Four types of controlsystems that involved vehicle-highway interaction wereaddressed: collision avoidance, speed and headwaykeeping, automated highway, and automated guidewaysystems. The distinction between automated highwaysand automated guideways is that automated guidewaysuse modified vehicles and some form of physicalguideway, while automated highways have intelligentvehicles guided by signals or electronic detectors.

In the sections that follow each of the ten systemcategories are described in terms of their function andcomponents, and illustrated by real-life examples wherethey exist. Following the system description we presenta summary of the panelists' perspectives onconsequential barriers, social impacts, driving forces,and required government support.

AUTOMATIC TOLLS AND ROADPRICING (ATRP). These are systems that canidentify individual vehicles in traffic and assess tolls onthe basis of usage and other factors. This is ac­complished without the effort on the part of the driver ora toll collector. The typical system requires severalfunctional elements including: a vehicle-mountedtransponder or tag; a roadside sensor; a computer systemfor processing and storage of data; and a billing systemfor assessing and collecting user fees. ATRP may beconsidered a combination of two systems. First, there isan automatic vehicle identification (AVI) svstem thatidenti0es the individual passing vehicles. 'Four types ofdetectlOn are used for vehicle identification: (1) opticaland infrared, (2) induction loops, (3) radio andmicrowave, and (4) surface acoustic waves. Then, thereis a computerized charging and billing system thatdetermines the fees based on the time of day, location,and congestion levels. Systems of this kind are currentlybeing implemented in Dallas Texas, Jacksonville Florida,and on the Dulles Toll Road in Virginia. Earlierexperiments were conducted by the New York and NewJersey Port Authorities, Caltrans and the Golden GateBridge Authority. An advanced electronic road pricingsystem (ERPS) received extensive testing in HongKong.

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The panelists viewed the primary advantage of thissystem over standard toll systems to be relief ofcongestion at the toll areas and time savings for themotorist. The economic efficiency of user fees was alsoviewed as an advantage, offering the ability to targetspecific vehicle and driver characteristics, and toimplement peak-hour pricing as a means of managingcongestion and redistributing highway costs to roadusers. The public transportation manager would also beequipped to measure the public's imputed value for newtransportation projects and services.

Most panelists agree that "road pricing to reduce ormodify demand may not be accepted by the public."This was the primary barrier to implementation ofATRP. Other barriers suggested by the panelistsincluded low system reliability at high speeds, expensiveequipment maintenance, and resistance to possibleviolations of civil liberties. The panelists expected re­sistance to systems that could provide the means ofmonitoring individual travel; this would be viewed bymany as an invasion of their privacy.

To facilitate adoption of ATRP the appropriategovernmental authorities would be expected to pass therequired enabling acts. The federal government wouldbe expected to help by establishing equipment standards.The Federal Highway Administration would need toacquire broader powers to upgrade sections of theinterstates into toll-billed sections. State and local~overnments would have to legislate the authority to1Il1plement ATRP and fund the necessary improvements.

Table 5 presents an overview of considerations thatare unique to ATRP. In addition to the items listed in thetable there are a host of other cross-cutting concernsapplicable to ATRP that are described above and atgreater length in the section of cross-category analysis.

Table 5. Items of Special Interest for ATRP

Driving Forces Barriers Government Impacts

• Redistribution of • Resistance to user fees • Address problem of • Reduced peak-hour traf-highway costs to users rights to road access fic

• Allocation of costs on • Resistance to invasion • Powers needed to up- • Less resistance to tol1sbasis of vehicle at- of privacy grade interstates to tolltributes roads

• User fees new source of • Increase state and local • Risk of invading pri-highway funding funding for ATRP vacy

• Measure public's im-puted value for projects

AUTOMATIC VEHICLE LOCATION(AVL). Advanced communication systems wouldallow fleet managers to monitor vehicles in the field anddeploy them more efficiently. This is the primaryfunction of AVL systems which provide vehicle locationinformation to a central authority. The methods forlocating the vehicles are, in most cases, identical to thoseused in automatic vehicle navigation (AVN) systems.Locations are determined through dead-reckoning,proximity beacon, GPS satellite, or Loran-C radiofrequency navigation. This information is transmitted toa control center where locations are presented ascoordinates or on a video mapping system. Locationinformation can be used with fleet management softwareto dispatch vehicles most efficiently. One example ofthis type of system is IT-Morrow's Vehicle TrackingSystem (VTS) that is being used to dispatch emergencyvehicles in the City of Detroit This implementation ofAVL has six dispatch stations which monitor some 760police, fire, and emergency vehicles. The vehicletracking system, operating on the Loran-C navigationalnetwork, allows dispatchers at computerized graphicworkstations to route the nearest vehicles to the scene ofan emergency.

This type of system would be of most use to fleetoperators and dispatch services; with their increasingcomplex distribution logistics AVL could improvemanagement of "just-in-time" deliveries where trucks~ould serve as mobile warehouses, reducing delivery andmventory costs. It could also facilitate charging usage

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for routes and reduce traffic congestion by routing trucksalong more efficient paths. With this secondaryreduction in congestion vehicles without AVL wouldalso benefit The panel expected AVL to lead toimproved truck driver performance, resistance by truckdrivers to retain privacy, and increasingly sophisticatedmethods employed by truck drivers to evade detection bythe systems. The ability to locate vehicles would alsodeter hijacking and improve the recovery of stolengoods. With large-scale public tracking systems thegovernment authority could conceivably assess userfees, although this is seen as highly unlikely in thecurrent social and political environment

Nevertheless, sluggish demand due to questionablecost-effectiveness and low user acceptance would serveas the major barriers to market penetration. Invasion ofprivacy would be as big an issue in private fleetmanagement systems as it would be in public dispatchsystems. In public systems there would be great concernover who would do the monitoring and how it would bedone, also who would pay for the system. Technicalconsiderations were not recognized by the panelists asmajor barriers. The panelists expected that it would takesome time to compile map databases that were requiredfor map matching.

The government would have several roles in supportof AVL. State and local governments would need tocommunicate the need for emergency dispatch and publicfleet management, perhaps eventually requiring uniformand economically effective systems in major urban areas.

The federal DOT would have to provide support through leadership and assistance with system planning.

Table 7. Items of Special Interest for AVN

Table 6. Items of Special Interest for AVL

Need for new sources of • Opposition on basis ofhighway funding right to privacy

none

Impacts

Impacts

• Risk some loss of pri­vocy

• Efficient dispatch andfleet management

• Improved fleet andgoods monitoring

• Charging usage forroutes

none

map and using adeductive algorithm. Each approachhas a particular set of devices and configuration. All fiveexisting methods may be used separately or incombination, and other methods under development maysupersede these in the future.

A number of automobile navigation systems are atvarious stages of development and testing worldwide,some of which have already reached various markets inlimited application. The Toyota Crown offers the optionof an AVN device to the upscale consumer market inJapan; it has been a popular option.

The primary advantage offered by AVN was reducedtrip times for the system owner, according to our panel.Small reductions in congestion due to improvedknowledge or route alternatives was ranked second bythe panelists. However, a navigation device would notdisplay nonrecurrent congestion and therefore would notfacilitate incident detection and traffic diversion.Reduced driver stress was also noted as a benefit of thesystem. Convenience and novelty were seen as benefitsthat would appeal to the consumer and would lead toearly adoption. There was some dispute over whetherANY would increase vehicle safety. While some of thepanelists predicted increases in safety due to benerinformed drivers; others viewed the in-vehicle monitor asa distraction, possibly resulting in less safe drivingconditions. Drivers' responses to display monitorsmounted on the instrument panel is a crucial humanfactors issue that needs to be addressed in the nearfuture.

human factors considerations and perhaps agreement ontechnical standards, technical issues were not seen asprominent barriers. The panelists did expect somedifficulty in compiling huge map databases required foruse in the map-matching systems. The question of legalliability for possible damages, injuries, and deaths whileusing a navigation system was tied to the safety questionand seen as another possible barrier to widespread use ofAVN.

Government

Government

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• Demonstration andpublic awareness pro­jects

Barriers

Barriers

• Public-private sectorcooperation

• Lack map database

• Justifying public fund­ing for public systems

• Settling who will pro­vide, operate, and main­tain

• Lack complete mapdataOOse

none

Driving Forces

Driving Forces

• Complexity of com­mercial distributionsystems

• Industry's need for effi­cient delivery

• Trend toward automatedbilling

Cost was seen as the primary barrier to marketacceptance. As one panelist commented, "the majority ofco~sun:ersare unlikely to purchase a stand-alone systemur.,ess It costs 50 to 100 dollars." It was questionedwhether a system could be designed and installed at a~nce acceP.table to the general consumer. Closely related~o the cost Issue was the prospect of building consumer.tcceptance and demand. Could the anticipated benefits~ sold to the general buying public? Other than the

AUTOMATIC VEHICLE NAVIGATION(AVN). Automatic vehicle navigation uses a variety ofmethods to determine the present position, heading,direction and/or distance of the vehicle in relation to aselected destination. The driver is infonned of hisposition relative to a selected address and/or the existingstreet geometry, helping the driver navigate the vehicle tothe desired destination. These systems would generallyinclude devices for positioning, stored digital road maps,a computer, and some fonn of visual display or voicesynthesis.. Navigation techniques currently under development

include dead reckoning, proximity beacons, ground­based radio (e.g., Loran-C and cellular), satellite, andmap matching. Dead reckoning calculates the vehicle'sposition by keeping track of the vehicle's travel distancesand directions from a known starting point. Proximitybeacons communicate location infonnation to thevehicles using short-range radio, microwaves, ormfrared signals. Loran-C is an example of a radionavigation system in which the vehicle's position isdetermined from differences in the arrival time of signalsfrom three or more land-based transmitters. The NavstarGlobal Positioning System (GPS) will have 24 satellitesspaced in orbits to enable vehicles to detennine theirpositions by analyzing the travel times of signals from atleast four satellite transmitters. Finally map matchingmethods, like that used in the Etak Navigator, useartificial intelligence to locate the vehicle by comparingthe vehicle's path with the road patterns of a digitized

Many of the panelists submitted that the governmentshould not be involved in the development ofautonomous vehicle systems beyond the naturaladjudication of liability complaints and possiblyfacilitating the setting of standards. However, somepanelists viewed the role of government in thedevelopment of AVN to be a provider of adequatefunding for research and development. If this is thecase, a suggested topic for research funding would bethe human factors considerations in AYN because of thepublic safety concern and liability questions. In systemswhere ground equipment is required, as with proximitybeacons, the government would be required to possiblyfund, install, and maintain the equipment, or at leastmonitor the operations of a contractor.

MOTORIST INFORMATION (MI). This isone of the more eclectic system categories representingall systems that communicate travel, traffic, road, andvehicle information to the motorist. Applications mightinclude digitized road maps, local traffic regulations,emergency broadcasts, public service messages (e.g.,weather, traffic, incidents, construction, parkingavailability, etc.), roadside service infonnation (e.g.,service stations, food and lodging, rest areas, shopping,etc.), and other forms of information either useful orentertaining to the motorist. Although automatic vehiclelocation (AVL) and automatic vehicle navigation (AVN)systems are closely related to MI, these two system typesare sufficiently distinct to have their own category andtherefore are not included here. Limiting MI to at mostone-way communication links, from an informationtransmission center and to the vehicle, distinguishes thiscategory from the two-way cooperative route guidance(CRG) systems.

External linkage may be provided through commonmobile communications techniques including proximitybeacons (e.g., lJHF, microwave, infrared), AM/FMbroadcasts, subsidiary carrier authority broadcasts,national weather radio broadcasts, land mobile radio, andpossibly cellular radio. A good example of anexternally-linked system is automatic interrupt radio pro­viding current traffic, accident, weather, and roadconditions for a local area Highway advisory radio(HAR) has been used for some time to inform driversabout traffic congestion due to highway construction,large events like football games, or seasonal airport use.Some Ml systems include autonomous data storage andprocessing capabilities containing relatively staticinfonnation of interest to the motorist. Examples ofstatic information would be electronic yellow pages ortourist infonnation. However, even in these examples, alinkage with the highway side through AVN would helpkeep the selection and processing of the most relevantstatic information for display to the motorist. Mobileoffice capabilities are also included under this categoryproviding features to assist in office communications,freight management, and database management.

Several fonns of these systems have already beenintroduced on a limited basis in Europe, Japan, and theUnited States. These include highway advisory radio,the Gennan ARI (Autofahrer Rundfunk Information) andARIAM (ARI aufgrund Aktueller Messdaten) systems,and the European Radio Data System. As mentionedearlier, highway advisory radio has been in use in theU.S. for quite some time. One panelist from agovernment agency related that "we have seven systemsin operation, some using digital voice storage (remotely

1370

changed), and others using AM band 530, 1610, and1200 KHz." The panelists were also aware of the theEuropean Broadcasting Union's ongoing implementationof the Radio Data System (RDS) in the UK, theNetherlands, France, Germany, and Ireland. RDSenables digitally encoded data to be superimposed on thesignal of a conventional FM broadcast and decoded by asuitably adapted car radio. Most panelists noted that inthe U.S. some of the regional coverage functions werealready available through standard commercial radio traf­fic advisories. One quote summarizes much of thediscussion on these systems in the U.S.:

The key word is "system." Ad hoc advisoryservices are not sufficiently standardized orf1ltered to merit the "system" title. Forexample, C.B. (citizen band) radio is an ex­ercise in anarchy, and will never be useful indense areas such as Los Angeles, though it isquite useful in the Mojave desert."

The panelists agreed that the most important benefitfrom a MI would be reduced trip times as a result ofdiverted traffic and reduced congestion in incident areas.Diversion would be achieved by informing drivers oftraffic incidents and conditions; the driver would thenpresumably avoid problematic areas by altering routesand departure times, or by possibly eliminating the tripaltogether. Diversion of traffic would have the relatedeffect of increasing the burden of secondary roads.However, the total throughput of the system would beincreased. Modification of the demand patterns andinfonnation of weather, traffic, and road conditionswould also result in increased traffic safety, as the driverwould be more aware of nonrecurrent hazards on theroad ahead. Related impacts would include energyconservation, improved air quality, and perhaps somelong-run modifications of land use patterns. Commercialusers might find that traffic infonnation would result inmore efficient operations and lower transport costs.Although it was mentioned, pleasure trip planning andeven business service information was not viewed by thepanelists as a significant force in adoption as comparedwith general traffic information.

Again, the panelists viewed cost as the mostsignificant barrier to market penetration. The cost to thevehicle owner, the manufacturer and supplier, and theagency in charge of maintaining the infrastructure andproviding the information were all of primary concern.There was some dissent on this issue because a basic MIwould demand a relatively inexpensive and slightlymodified car radio that most panelists thought would beaffordable. However, the implicit costs of informationdistribution were a matter of greater concern. Collectionof current traffic information and maintaining the Mldatabases were seen as especially formidable tasks. Onepanelist observed that while RDS is already available inEurope, "the complex issues in the U.S. are (1) toestablish the infrastructure, and more so (2) to create theupdated information on relevant geographic basis."There was a general belief that this would take acommitment to generate a nationwide network ofcompatible systems with common communicationprotocols and broadcast standards. Cooperation betweenpublic and private sector providers, including decidingon who will provide the service and deciding on whowill pay for the devices, infrastructure, and information,was seen as another significant hurdle. Technical issues,other than ensuring technical reliability, were not seen as

Table 8. Items of Special Interest for MI

Driving Forces Barriers Government Impacts

• Public's awareness of • Task of keeping the in- • Support for public-pri- • Redistribution of trafficavailable information formation current vate cooperation from primary to sec-and technical capabili- ondary roadsties

• Recognized commercial • Public-private coopera- • Commitment to na- • More effective use ofpotential tion and coordination lion-wide network of transportation facilities

information centers

• Reduced energy con-sumption for vehiclemiles traveled

• Improved air quality

barriers.SUggested government involvement included (l) the

ovisi;n of adequate funding for installation,~aintenance, and operation of the information controland broadcasting centers, (2) supporting theestablishment of equipment standards, and (3) the

COOPERATIVE ROUTE GUIDANCE(CRG). A logical exte~sion C?f the ~oto~st .infonnation and automauc vehIcle navlgauon systems ISto establish two-way communication between the vehicleequipment and a traffic control center. The adv~ntageofthese closed-loop systems over one-way motonstinfonnation systems described above is that (1) the~affic control center can monitor specific vehicles toImprove their assessments of area-~ide traf~cconditions, and (2) they can potenually provIde betternaviaation information to the driver by taking account ofreal-~ime traffic conditions. CRG systems are of twotypes: those which use long-range radio broadcasts tolink the vehicle with a traffic control center, and thosewhich also use short-range communications to link thevehicle to roadside infrastructure (Castle RockConsultants, 1988).

An example of the first type is the Pathfinderexperimental demonstration project that is designed totest the feasibility of using a CRG to assist motorists inavoiding adverse traffic conditions. The experiment,which is a collaborative effort between the FederalHighway Administration (FHWA), the CaliforniaDepartment of Transportation (Caltrans), and General\toters Corporation (GMC), is being conducted alongthe Santa Monica Freeway in California. In this case theCRG configuration includes an Etak Navigator linked byradio to a packet radio system, which, in tum, is linkedbv radio to a central workstation, providing two-way_l~mmunicationbetween the workstation and the vehicle.The motorist sends information on the vehicle's location,he:lding, and speed via radio link to the central\\'orkstation, where it is processed along with freewayand arterial data to determine real-time congestion levels,and later relayed back to the equipped vehicles. Themotonst receives information on the levels and locationof congestion in the form of symbols on the Etak\;avigator, text, and voice synthesis. The Advanced"lobile Traffic Information and Communication System!:\\1TICS) being tested by the Japan's National Police-\gency is a similar, but more comprehensive system,relying on a teleterrninal system for small-zone radio,ommunication, combined with static service information

1371

provision of incentives for support of public/privatecooperation. This would require commitment toestablishing a nationwide network of control centers andprovision of the right of way for the essential infras­tructure. Federal funding of research and developmentwould also be required.

supplied through recording medium.Examples of systems using short-range

communication and beacons are ALI-SCOUT in WestGermany, AUTOGUIDE in the United Kingdom, andthe Road/Automobile Communication System (RACS) inJapan. The ALI-SCOUT system is a cooperative effortby Bosch/Blaupunkt and Siemens using post-mountedinfrared transceivers along the roadside and dead­reckoning navigation in the vehicles providing somecomputational capability in the vehicle as well as two­way communication between the vehicle and a centralcomputer. Equipped vehicles transmit their travel timesto the beacons, which are then relayed to a centralcomputer where they are used to calculate routerecommendations. These recommendations are then re­layed to the beacons and transmitted back to the vehiclealong with pan of a city map. The AUTOGUIDEsystem being tested by the Transport and Road ResearchLaboratory (TRRL) in London is similar to ALI-SCOUTin that it uses infrared transceivers mounted on beaconsto to establish two-way communication between theequipped vehicles and a central computer. The JapaneseMinistry of Construction's RACS demonstration alsouses a similar approach, but relies on microwavecommunication between the vehicle and the beacons. Inaddition, the two-way communications include voicemessages and facsimile services between the motoristand a wide range of locations (home, office, etc.)beyond the central computer similar to, but much simplerthan, cellular telephones.

With current real-time traffic information the trafficcontrol center has a greater capacity for effective trafficmanagement. According to our panelists, the mostsignificant impact will be diminished congestion, closelycoupled with reduced travel times for the individualdriver using the system. With the traffic distributedmore efficiently throughout the network the panelistspredict related improvements in driving convenience,traffic safety, traffic flow, fuel efficiency, and airquality. CRG may also be used in lieu of vehiclelocation and dispatch systems to increase the efficiencyof fleets. Somewhat removed from traffic impacts isanother major consideration and possible benefit --

technologies for vehicle to roadside communication ofboth data and voice, radio frequency allocations, andcommon in-vehicle circuit boards. Coordination andplanning of system research, development,demonstration, and implementation was the last majorbarrier mentioned by the panel. The enormous scope ofthis endeavor and the large number of parties involvedmakes the introduction of CRG a complex and difficultadministrative and political conundrum. Of all thesystem categories, CRG probably requires mostcooperation among most parties. Where should we start-- with the vehicle or the control center? Who willprovide the leadership -- government or industry? Howwill the efforts of industry and government be co­ordinated? These are difficult questions that will have tobe answered in order to mount a collective campaign.The panelists also identified the resolution of liabilityissues and assuring system reliability as concerns forimplementing CRG.

""~__. __M ------------ a

international competitiveness in intelligent vehicle andhighway technologies. This may be seen as a drivingforce for adoption in the U.S. because of the concern forindustrial and technological competitiveness Thepromise of major national contracts for suppliers of thesystems is seen as another driving force.

The panelists ranked cost, both public and private, asthe primary barrier to market penetration. The cost of in­vehicle devices and the roadside infrastructure, and howthe costs will be allocated, are of critical importance.The end-user's perceptions of benefits and costs,whether from the perspective of a potential customer orpotential taxpayer, will ultimately determine the successof CRG. Assessing and communicating the likelybenefits is another element of this obstacle. Innovativeschemes for cost allocation may be essential. Beyondcost considerations, the federal government needs to beinvolved in establishing standards and ensuring com­patibility between commercial systems. Issues forgovernmental standardization bodies to address include

Table 9. Items of Special Interest for CRG

Driving Forces Barriers Government Impacts

• Public's awareness of • Conflicts over distribut- none • More effective use ofavailable infonnation ing and allocation of transportation facilitiesand technical capabili- coststies

• International competi- • Reduced energy coo-tion sumption per vehicle

mile traveled

• Improved air quality

COLLISION WARNING (CW). In-vehiclewarning systems caution the driver when on a collisioncourse with another vehicle or object. Not only is thearea in front of the car scanned to detect a rapidly closingpotential collision, but the driver's blind spots in the rearoutermost comers of the vehicle are monitored tofacilitate lane changes in traffic. Once an obstacle isdetected a signal or message is delivered to a display onthe instrument panel, the windshield (as in a head-up dis­play), or on the rear-view mirror (e.g., for lanechanges). The detection component of the system can bebased on radar, sonar, infrared, or laser technology.Laser, radar, and infrared are generally preferred forfront and rear interval control in existing applications.Ultrasonic waves are likely to be used for monitoringblind spots on the side of the vehicle. CW systems areto be distinguished from incident detection systemswhich provide motorists with information concerningcollisions and other incidents far enough in advance sothe motorist can modify his or her route. GeneralMotors (GM) has equipped a number of their vehicleswith near obstacle detection systems (NODS) that warnthe driver of objects that are in the near-field vehicle'spath, but are not necessarily in the driver's view. Onevehicle has a detector mounted near the back bumper towarn the driver about objects while backing up. AnotherGM vehicle warns the driver of objects in the blindspots.

Collision warning systems represent a distinctcategory of IVHS and a step toward automated vehiclecontrol. The purposes of CW and collision avoidance(CA), the first automated control system to be addressed,

1372

are similar, and they share sensor and detectiontechnologies. However, the functions are distinct;collision warning systems inform the driver of oncomingobjects while collision avoidance systems send signals toprocessors and actuators that control the vehicle brakingand throttle functions. Although the systems are related,collision warning is unquestionably a driver advisoryfunction, just as collision avoidance is certainly a controlfunction.

The primary motivation for the development ofcollision warning systems is the desire to reduce trafficaccidents, fatalities, and property damage, and toimprove overall traffic safety. Trusted CW systems havethe potential to relieve some of the stress and fatigue ofdriving. A related benefit would be reductions ininsurance rates for drivers of modified vehicles.However, should CW become widely accepted bymotorists, the panel also expected an antagonistic drifttoward increased driver risk-taking. So there is atradeoff between faster vehicles and relief of driver stressthat will ultimately be settled by decisions on appropriatespeed limits. If the speed limit is increased and thenumber of traffic incidents does not increase, thenincreased system throughput would also be expected.When, and if, CW systems are proven to be reliable,consumers may become more likely to trust otherwarning and control devices. This is where CWbecomes an entree to more advanced automated controlsystems, especially collision avoidance systems.

According to our panel the serious impediments toconsumer acceptance of CW are of a technical and legalnature. These also apply, perhaps to a greater degree, to

1373

Table 11. Items of Special Interest for CA

Driving Forces Barriers Government Impacts

• Legal requirement on none • Encourage insurance • Increased litigationnew vehicles differentials for

equipped vehicles

operation. A reliable CA system should offer a morerelaxed environment for vehicle operators with andwithout CA installations. With fewer accidentsinsurance rates should fall. Differential insurance ratesshould be provided for drivers with CA installations.The panelists also predicted increased use of theautomobile relative to other modes of transportation andperhaps increases in congestion with greater throughput.

System reliability is the principal barrier todevelopment of an effective system. The panelistsagreed that "trusted" or "fail-safe" system design was theprimary concern for CA. This appears to be a criticalresearch and development issue. There was alsoconsensus that liability might be too great for componentmanufacturers and government to implement such asystem, even if it offers the potential for aggregateimprovements in traffic safety. One panelist pes­simistically asserted that "the U.S. legal climate almostdooms such technologically refined systems from thestart." Another issue that is unique to the automaticcontrol systems is the driver's acceptance of activecontrols. Panelists expressed uncertainty about whetherdrivers would want or use such a system even if it wereavailable at a reasonable cost They may feeluncomfortable with the loss of control. As with all thesystem categories, cost and consumer demand were alsoa concern.

Driving Forces Barriers Government Impacts

• Possible savings on none • Demonstration and • Increased risk taking byauto insurance public awareness pro- drivers

grams• Possible legal require- • Encourage insurance • Increased consumer

ment on new vehicles differentials for !rust in non-human sys-equipped vehicles terns

• Technological advances • Motorists will drivein automated control fastex

coIlision avoidance and the automated control systems cost to the consumer. Consumers may have to bethat will be discussed in the next section. The panel em- educated and convinced that CW is worthwhile.phasized that system reliability must improve for The panel suggested that the federal government willwidespread acceptance of CWo Accordingly, system be called upon to take a leadership position in paving thedesign must address detection and diagnosis of incipient way for collision warning. This will entail providingfailures. Target discrimination must be near-perfect and adequate funding for research and development,false alarms must be kept to a minimum. A related coordinating and financing demonstration projects,concern is liability. To what extent will private vendors assuring unifonn implementation of selected systemsand public agencies be liable for accidents when the among the states, modifying the roadways if required,svstem is in use? According to one of our experts, and establishing technological and perfonnancecUrrent CW systems have "excessive false alarm and standards. Undoubtedly the paramount issue facingerror rates compared to humans -- the liability potential is &overnment will be liability. The legislative system isfrightening." Performance standards and inspections are likely be called upon to to resolve the inherent threat oflikely requirements. Finally, the benefits must offset the increasing manufacturer liability.

Table 10. Items of Special Interest for CW

COLLISION AVOIDANCE (CA). Automaticbraking is the principal component of a collisionavoidance system. CA is a logical extension of thecollision warning (CW) which detects rapidlyapproaching obje~ts but ~oes notyrovide a~tomaticbraking for the driver. Like CollISIon wammg systems,CA systems use radar, sonar, infrared, andlor laserdetection to sense approaching targets. However, oncean approaching object is detected signal is sent to a signallJrocessor which calculates and analyzes the distance andrelative velocity of the object, as well as the groundspeed of the vehicle, to determine the probability ofcollision. For example, if a collision is deemedprobable, electromagnetic actuators may deploy thebrakes to an appropriate degree. Radar technology iscurrently the preferred approach because it is the mostresilient in inclement weather. Throttle and steeringcontrol are other possible elements of an advanced CAsystem but is not considered in this discussion orprojection.

As with collision warning, the interest in collisionavoidance stems from the desire to reduce trafficaccidents, injuries and fatalities, and property damage,and to generally improve traffic safety. The panelistsranked safety far above the other projected advantages.The second leading advantage from CA was easingdriver stress by providing backups for safer vehicle

The panelists saw the government getting involvedby helping to limit public and private liability, settingstandards, funding and offering incentives for researchand development, and offering purchase incentivesthrough schemes like reserving special lanes forequipped vehicles.

SPEED AND HEADWAY KEEPING(SHK). These systems combine throttle control withpossibly some limited radar braking capabilities in orderto assure safe and efficient distances between vehicles onthe roadway. Current implementations of throttle controlcustomarily employ pneumatic servos which operate thethrottle in response to a vacuum obtained from theengine's intake manifold. Cruise control is one form ofthrottle control that responds to feedback on vehiclespeed. As in the collision avoidance (CA) systems,radar braking would involve target sensing, signalprocessing, vehicle ground speed measurement,command logic and controls, and electro-mechanicalactuators. However, in the most basic system"intelligent cruise control" would only employ throttlecontrol, and perhaps some light braking, adjusting thevehicle's speed in light of information on road and trafficconditions, speed of other vehicles, obstacles, and/orelectronic speed limits. SHK systems promise to allowfor shorter headways between vehicles therebyincreasing the capacity of the roadway. For example, anumber of similarly equipped vehicles would be able toform a platoon, with compressed headways, and travel atrelatively stable speeds. Like cruise control, SHK alsopromises to reduce the overall driving effort. Onepanelist reported that Volkswagen, Mercedes-Benz, andthe German Army Research and Development Centerhave demonstrated driverless control at 100 kilometers

per hour with clear lateral defmition. The MartinMarietta Autonomous Land Vehicle is a similar concept.

The panelists indicated that safety is the mostimportant benefit of SHK. Safety is likely to be thedriving force for adoption and eventually for mandatoryuse. Increased throughput and traffic efficiency is alsoimportant. The possibility of reducing headways andplatooning vehicles promised to improve traffic flow andresultant travel times. The panelists also noted that theconsumers may desire SHK because it reduces the effortand stress of driving, although some consumers may notprefer active controls. One can draw a parallel withcruise control; some drivers cherish cruise control,others are uncomfortable with it Unless cost is pro­hibitively high consumer demand is not likely to be amajor issue.

Again, system reliability is expected to be the majorbarrier to market acceptance. Reliable system design islikely to be the central thrust of most research anddevelopment efforts. In the institutional domain theliability issue is again present. If the manufacturers areheld completely liable for accidents while the systems aredeployed they are not likely to make the system availablefor widespread use. Demand will be influenced by priceand performance. Production costs and market price willbe of central concern to the manufacturers. Theconsumer will demand proven reliability and safety.

According to our panel the government must takesteps to limit corporate and government liability. Theyalso suggested that the government take steps toestablish effective standards and to increase funding forresearch, development and demonstration. Federal orstate governments could also playa role in periodiccertification of in-vehicle subsystems.

Table 12. Items of Special Interest for SHK

Driving Forces Barriers Government Impacts

• Desire to reduce insur- none • Periodic certification of • Increased efficiency inancerates in-vehicle subsystems traffic flow

• Vulnerability to control\n>.akdown

AUTOMATED HIGHWAY (AH). This is themost advanced form of vehicle control, combiningelements of speed and headway keeping (SHK) andcollision avoidance (CA), and adding further controlfeatures, to enable vehicles to travel on their own,without any form of continuous control by the motorist.Vehicles would be totally automated in all aspects of con­trol. In an automated highway environment the vehiclewould, in effect, operate itself, taking itself from originto destination according to programmed instructions.Elements of the total control function have beendiscussed under SHK and CA. However, AH requiresmore than automated steering, braking, and throttlecontrol. The AH concept calls for full longitudinal andlateral control of the individual vehicle combined withautomated approaches for navigation, entering,egressing, and merging. All issues of control at both themicroscopic (individual vehicle) and macroscopic(traffic) levels would have to be resolved. Furthermore,the control systems would have to be fail-safe. Many ofthese issues have been addressed in the development ofautomatic guided vehicle systems (AGVS) which have

1374

been implemented for materials transport in factories andfor traversing hazardous areas. However, the routingand control problem is much more complex in a dynamichighway environment.

Because the full implementation of AH is expected tooccur far into the 21st century the benefits of AH are alsoviewed in this time frame. The panel expected AH tocome to fruition at a time when society will be facingintolerable traffic congestion on urban freeways. TheFHWA has projected that urban freeway travel willincrease almost 50 percent up to 492 billion vehicle-milestravelled by the year 2005; total traffic delay in 2005 isexpected to be five times the 1987 delay. This level ofdelay is difficult to imagine, but if this is the case, whatlevels of delay can we expect for the year 2050 when AHis expected to reach majority use? It is hard to say, buttime savings and increased vehicle throughput were seenby our panel as the most important impacts of AHsystems. Demand for AH would be the greatest in themost densely populated areas, although rapid intercitytravel might also have some support. The panel ac­knowledged the need for other modes of transportation

Table 14. Items of Special Interest for AG

Table 13. Items of Special Interest for AH

Impacts

Impacts

• Debates over whether toallocate resources toequipping lanes androadways

• Diminished freedom ofmobility

• Changing employmentopportunities in trans­portation sector

• Reduced need for truckdrivers

• More reliable trip times

• Increased recreationalvehicle travel

• Huge guideway build­ing program

travel would increase on all modes for trips up to 500miles. There could also be a shift from the airlines to theautomobile as shoner intercity trips were made on AHsystems.

The principal barrier to developments in AH wastechnical reliability and trusted system design. Liabilityand cost were the other predominant issues. Onepanelist contended that AH would "require enormousamounts of government funding, on the order of puttinga man on the moon." Technical barriers included neededadvancements in sensing, information integration, andvehicle control as described in the introduction above.Inter-vehicle dynamics were viewed as an irnponantissue, especially the integration of equipped and non­equipped vehicles in the system. Many of the controltechnology issues were the same as with CA and SHK.

elevated guideway or around a closed loop; the DetroitPeople Mover would be an example, but this is not thetype of system that the panelists addressed here. Thedual-mode form of automated guideway was addressedby our panel where private vehicles are used in aconventional way in local traffic but are switched to aguideway in dense corridors. One could imagine asystem where everyday vehicles would travel on theconventional street system in most areas and then switchto a specially equipped guideway at cenain access pointswhere pallet cars would carry the vehicles along a guidednetwork. The pallets would conceivably move thevehicles with shon headways at a uniform and fastspeed. Dual-mode mag-lev systems also fall mto thiscategory. The key distinction between AG and AH isthat AG uses standard vehicles and some form ofphysical guideway whereas AH has intelligent vehiclesguided by signals or electronic detectors.

Government

Government

• Establish a federal op­erating organizationsimilar in scope toNASA

• Improve roadway stan­dards and maintenance

1375

• Funding for construe­tion and operation ofguideways

• Building of guideways

• Acquire right-of-wayfor guideways

none

Barriers

Barriers

• Guideways are fixedroutes which limit mo­torist flexibility

• AG is in direct compe­tition with AH

Driving Forces

Driving Forces

• Increasing dispersion ofpopulation in noncon­tiguous urban centers

• Trend toward increasingautomation

• Use of guideways tocomplement othermodes

• Inefficiencies of short- • Limited access to ap-range air travel proved vehicles

• Desire for improvedmobility

Our panelists believed that the federal and statewvemments would be called upon to fund thejevelopment of AH systems. They would have to be.:ommitted to funding research, development, anddemunstrations over the long haul if advances were to bemade. Many of the panelists believed that a new federaloperating organization would be required approachingthe size and scope of NASA. At an operational level thegovemment would coordinate transponation planning,:ertify vehicles, restrict access to dedicated lanes, and:mprove roadway standards and maintenance.

AUTOMATED GUIDEWAY (AG). This:ategory aims to combine the advantages of automatedgUideway transit (AGT) and normal street vehicles..\,GT is a class of transportation systems where~nmanned vehicles travel along guideways with~,,-'lusive right of way. A common form of AGT is the~rhJ.I1 shuttle which moves back and forth an a single

;n this congested environment, but they predicted that the~LJtomobile would still be needed to access contiguous,hil!h-dens~ty populatio~ areas as a ~omplement to bus,1.111. and au transponaoon. Assurmng that these systems

auld not reach the market unless they were completely~liable, the other predominant impact is increased traffic<;:1fetY- Another of the primary benefits was reduceddriver stress.. Some expected negative impacts included debatesover where these systems would be implemented,diminished mobility as travel gradually moved from thenon-equipped auto~obi~e to AH.syste~, ~d ~~jo~-hanges in the trucking mdustry mcluding dirmmshmg~eed for trUck drivers. If throughput was increasedsignificantly one would also expect a significant changein land-use patterns. One panelist predicted that personal

ic

ld

p

The panelists viewed the primary benefit of AG asbeing increased throughput and faster travel times. Itwould not require major alterations of the vehicles asautomated highways would require. The primaryimpediment to the development of AG was what thepanelists viewed as a competitive disadvantage with AH.Most panelists saw AH as a more feasible alternative.Other barriers included the need of the right-of-way andconstruction of a guideway, the cost of the publicinfrastructure, and the physical intrusiveness of theguideway. There was a general skepticism whethersystems of this type would ever be developed.

CONCLUSIONS

Thi~ Delphi study combined both exploratory andnormanve approaches to forecasting in order to assist theUM IVHS research planning project in anticipating near­term events and in developing a research anda~nis~tive strategy designed to meet realistic goals.The mdiVIdual systemforecasts were exploratory in thesense that they predicted market penetration on the basisof selected assumptions. The forecasts describe the~e~-te~ limits to IVHS developments given sufficientmsntutIonal support for these efforts. The listing offactors that may influence the development of thesesystems ~s ~re norrnativ.e in nature; these lists mayserve to Illurmnate potentIal opportunities and roadblocksalong the path to developing an IVHS capability in North~merica..Knowledge of these factors also helps toClTcumscnbe reasonable goals and strategies for researchand development in the area. This section describes thelimitations of the exploratory forecast and how thenormative assessment, along with our plan for periodicupdates of the Delphi study, provides a sound basis forformulating a research strategy in IVHS.

The .survey sho~s that progress in the development~d ~e trnplementatIon of IVHS will depend onSIgnificant technical and institutional advances over then<:xt ten years. The technical problems appear to befmly well-defined; the design of driver informationsystems being the most immediate technical concern andthe reliability of the advanced vehicle control systemsbeing the crucial long-run issue. The institutional~o~siderations are much less certain. Our surveyIndicates that the turbulent institutional environment hasthe potential. to slow, or even halt, the progress toward acompr.ehenslve IVHS capability in the U.S. In fact, themost likely and consequential near-term barriers todevelopment and implementation of IVHS are the pos­sible lack of consumer demand for and acceptance ofthese new transportation alternatives and the failure ofour institutions to support the cooperative developmentof IVHS. Thus, the successful implementation of IVHSin North America will require a concerted effort on thepart of the participating manufacturers, governmentagencies, and other interest groups to cooperate inresolving the issues of liability, standards, and supportfor research, development and demonstrations.Cooperation among the key participants will need tocontinue through implementation and operation of manyof t~e systems presented in this report because both thevehIcle and the highway elements will be fused into aunified whole. It is our opinion that existing institutionalarrangements are unlikely to provide adequate supportfor these efforts and that institutional innovation must be

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sought. The unconventional nature of the institutionalproblems ~sed by.lyHS limits our ability to predictrelevant SOCIal, pohtlcal, and economic events with anydegree of certainty.

I? his ~spect~ critiqu~ of forecasting methods inpubltc poltcy making, William Ascher (1978) contendsthat the predictive value of a forecast is determinedprimarily by the core assumptions on which it wasbased. If the co~e assumptions are uncertain or wrong,then the conclUSIOns of the forecast are likely tocorrespond. If the assumptions are accurate then theforecast is likely to have greater predictive v~ue.Ascher's insights have significant bearing on the strategyfor and use of forecasting in deliberations on the futureof.~HS. Because the ~nstitutional arrangements are socntlcal to the progress m IVHS, any forecast of technicaladvances in this area will be extremely sensitive toanomalies in the institutional arena.

~~ primary difficulty in providing accurateprechctlons of developments in IVHS is precisely that theenvir~n~ent for social decision making in NorthA~~nca IS C?I?plex and I"3:Pidly changing, limiting ourability to antIcIpate events In a turbulent institutionalenvironment. The core institutional assumptions for oursurvey were highly optimistic and uncertain; should theass~~ed institutional mechanisms fail to prOduce theantIcIpated levels of support, then the predictive value ofthe forecasts will diminish. For example, should thefederal government fail to support the development ofIVHS, or should the central institutional actors fail intheir efforts to collaborate in this area, then little progressshould be expected in the area of cooperative routeguidance, which requires substantial levels ofgovernment support and institutional cooperation.Therefore, the expert forecasts that resulted from thissu~e~ s~ould be v~ewed with an understanding of theoptImIstIc assumptIons on which it was based, and usedmox:e.as a tool for setting goals and making near-termdeclSlons rather than for predicting the long-run future.The optimistic exploratory forecasts are most useful inassessing th~ technological feasibility of meeting societalgoals regarding the development of particular systems.They should be interpreted as the lower threshold foradvancements in these technologies.. ~ith the limitations of our forecasting methodologyIn mmd we developed a strategy for anticipatinginstitutional events and technological breakthroughs forthe purpose of developing and revising our researchstrategy: ~irst, as the ~port refl~ted, we placed greaten:p~~sl.s In the DelphI s~ud~ 00; Identifying andpnor:nzmg a. numbt?r of ImpIngmg factors, includingpOSSIble ban:ters to trnplementation, driving forces fortrn~le~entatIon, government policy initiatives, and theSOCIal Impacts of IVHS. Knowledge of and sensitivityt~ these .factors will assist us ~ anticipating possibledifficultIes that lay ahead and In channeling our researchand ~ministrative efforts more effectively. We took arelatIvely open-ended approach in this portion of thesurv.e~ to encourage originality on the part of thepartIcIpants and to avoid the possibility of overlookingImportant factors. Second, it is our plan to repeat theDelphi on a periodic basis to update our assessments asevents unfold. This will help us avoid what Ascherterms "assumption drag" where the forecast relies on~::>utdated ~ore assumptio~s,which accounts for the grossInaccuraCIes of many policy-related forecasts. This

_.....-_._------

'rit:;ti Delphi study was designed with the intention to1~ovide a foundation for a series of similar studies in the~ears to come. For example, the structure of.~e. nextbelphi should emerge from the results of the IDIUal

study.. . al' ·th di thInstItutIon Issues notwI stan ng, e prospectsfor rapid development ~f intelligent vehicle-h~gh~aySystems in North Amenca suggest that orgamzatIons~ith stakes in t~e future of r<;>ad l!ansponation getorganized to gUIde progress ill this area and respondswiftly to opportunities as they arise. Motorists demandthe freedom of mobility delivered by the automobile. Tothe extent that IVHS can incre~se the thro~ghpu.t ofexisting roadways, reduce vehIcle travel urnes, IDcreasethe motorists' comfort, convenience and safety, andgenerally provide the motorist with information thateither makes the driving time less aversive, moreproductive, and possibly more entertaining, the motoristsfreedoms will be extended and a market for theseproducts will be assured. If IVHS can deliver theseadvantages as expected, the primary question becomesone of cost -- cost to vehicle manufacturer, automobileinsurance companies and ultimately the vehicle owner,cost to the government operating organization and thelocal taxpayer, cost to the Department of Transportationand the U.S. taxpayers. As the cost of these systemsrumble the markets for the products and services willsurface.

Elements of IVHS have already been introduced, butthe full market potential of IVHS will not be realizeduntil the key actors in the public and private sect9rscommit to a common vision of "smart" roadtransportation. The results of our Delphi survey indicatethat, under the right institutional conditions, thecommercial and noncommercial market will arise inrelatively short order. Majority commercial use of mostadvanced driver information systems is expected by theyear 2000. Adoption by the general public is not farbehind. This implies a lot of work between now and theimminent turn of the century. Research on systemintegration and the human consequences of IVHS mustbe supported and conducted at an internationallycompetitive level, systems must be designed anddemonstrated to be effective and reliable, new technicalstandards will need to be set, potential shifts in liabilityrisks must be reconciled, operating organizations mustbe established, and a host of other milestones must beaccomplished before a fully integrated and supportedIVHS capability is established in North America. Oursurvey of experts was directed at determining feasibleprogress in IVHS in the years to come and at issues thatwill require action if this is to be achieved. Perhaps theresults can serve to infonn the individual stakeholdersabout what is possible and to help shape a shared visionof IVHS in North America.

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