Fig. 2. Results for 2000

The Ministry of Land, Infrastructure and Transport and AHSRA are studying scenarios for the evolution of AHS. This work is now at the stage of soliciting views from various quarters. The work this year will begin, first of all, by providing sensors and other equipment developed by AHS so that they can be used for road management. We intend to speed up the use of information obtained through that application so that it can be used for the Vehicle Information and Communication System (VICS) and for raising the sophistication of existing information services. The next step will be provision of AHS services using information boards. When sensors pick up road surface information on freezing conditions, for example, then that information can be provided at the beginning of curves to notify drivers of dangerous conditions ahead. Added to VICS or other such systems, this information will be effective for drivers determining whether the road ahead is icy and in making decisions about whether it is necessary to prepare tire chains and so on. We hope to use the systems for applications of this kind. Although their operations will be conducted in testing mode, cooperative vehicle-highway services using spot communications are scheduled to commence from 2003. The basic flow of our activities from this year to 2003 will involve efforts geared to these various developments and applications and the initial deployment of cooperative vehicle-highway services. We will be moving toward the eventual adoption of more advanced cooperative vehicle-highway services using continuous communications some four to five years after that. To summarize this in very broad terms, we are studying scenarios for development of ITS infrastructure utilizing AHS, followed over the next several years by expansion of the number of users and improvement of the level of our services. (Fig. 3.)

Fig. 3. Scenario for AHS Evolution

Upcoming issues include incorporation in requirements of the results obtained from proving tests. Services for merging and diverging vehicles will be very manageable if speed controls can be enforced. If judgement and the use of information are left to user discretion, however, it will be difficult to provide effective services. Studies will be conducted to determine all possible ways of increasing effectiveness. Applied services will also be studied, as will services that use two-way communications. AHS communications are basically two-way. When it is possible for a cruising vehicle to pass on information about its status, for example if it is using its windshield wipers, then this will improve the prediction accuracy of road surface information, and that information can be provided to other vehicles. When a vehicle conveys the information that it has come to a stop, then it will be possible to provide stopped vehicle warnings and other such information even in locations that are not equipped with AHS sensors. This mode of communications thus has many advantages. On the other hand, there are also various other issues, such as vehicular privacy, the means for assessing the reliability of information sent out by vehicles, and the means of assuring such reliability. We intend, therefore, to consult closely with the vehicle side as we work to utilize cooperative vehicle-highway to full advantage. (Fig. 4.)

Fig. 4. Issues for the Future

2. Institutions and Standards

Various institutions, standards, regulations, and so on are involved in the move toward practical application of AHS services, and such actual use requires that they be investigated . We are engaged in study to find out which of these are applicable, whether we can comply with them, and if we cannot, whether the relevant laws will need to be amended. At this point, no major problems have been discovered. The below records a large number of institutions, standards, and statutes that illustrate what we are studying at present. We are soliciting ideas from everyone, so please let us know if you have any ideas or suggestions regarding points we should be concerned about, or perspectives we should account for. (Fig. 5.)

Fig. 5. Statutes Related to Institutions and Standards

AHS systems basically must be safe and must be highly reliable. Anyone involved in engineering will understand, however, that these systems cannot claim to be 100% safe and trouble-free. In that light, there are a number of proposals we are discussing that suggest possible approaches toward our goal, and that should be understood as such. The fundamental approach is maximum assurance of reliability and safety, and reduction to the greatest possible extent of malfunctions that entail danger. The fact is, however, that the systems will be used widely and frequently, and given that working assumption, we find it necessary to consider realistic measures that lie within a realistically feasible range. We intend to clarify applicable conditions, and proceed with countermeasures based on concrete analysis and cooperative vehicle-highway. (Fig. 6.)

Fig. 6. Basic Policy Regarding Reliability and Safety (Proposed)

Fault tree analysis (FTA) is one example of an approach to clarifying a number of actual conditions and devising measures to deal with them. FTA is a systematic analytical method for identifying the origin of a malfunction. This analysis is carried out, and items that obtain a passing evaluation can be left as they are. When items receive a conditional pass, the conditions must be clarified, and those items can then be used under those conditions. When proper conditions cannot be put in place, then technological measures to handle those unsatisfactory conditions must be devised. When such technological measures are not possible, then it will no doubt be necessary to take thoroughgoing information measures to inform users that the item cannot be used under those particular conditions. Even items that are difficult to resolve individually can sometimes be handled as systems, and it may be possible to devise resourceful vehicle applications that clear up some problems. We intend to take up all conceivable malfunctions and problems, and consider them thoroughly one by one in order to determine whether the system can stand up to their failure, and whether technological measures can be taken against them. (Fig. 7.)

Fig. 7. Measures Relating to Reliability and Safety

Fig. 8 shows a failure probability model. The vertical axis shows system functions and the horizontal shows human functions. The conceivable regions are normal function on both sides, system normal but driver committing an error, and the driver normal but the system malfunctioning. These malfunctions also include those that have little impact on safety. The other malfunctions, which represent phenomena with a high probability of resulting in great danger, are risk-side malfunctions, and these must be drastically reduced. Another situation that must be considered arises when the system operates normally to issue a warning, but the driver, thinking the situation is not urgent, takes no immediate action. This could reduce the effectiveness of AHS. We are taking this into account in analyzing what kind of systems will increase safety. Fig. 9 shows one such example, which envisions a situation where a sensor should detect a vehicle and pass on that information. If a sensor were to decide that no vehicle is present when one actually is, however, and the system were then to provide that information to users, then this situation would be extremely dangerous. Alternatively, the situation is satisfactory if the system can issue a clear announcement that my car has broken down, for another example, but it will be dangerous if the system is unable to announce the presence of such an obstacle. We are at the stage of considering whether such situations can arise, and if they can, then what specific measures should be taken for individual situations of that kind. (Fig. 8, Fig. 9.)

Fig. 8. Failure Probability Model

Fig. 9. Risk-side Failure

ITS standardization has a hierarchical structure. The present plan is to proceed with standardization of the common portions that underlie the actual individual services and that form the platform for them. We have assigned priority to standards related to common systems, in particular. Specifically, we have submitted a proposal to ISO/TC204, WG14 for information provision by the infrastructure to adaptive cruise control systems in order to promote more efficient utilization of those systems. The way was opened to proceed in that direction at a conference in April of this year, and we will be drafting proposed standards. We also hope to develop domestic JIS standards. (Fig. 10, Fig. 11.)

Fig. 10. Hierarchical Structure of ITS Standardization

Fig. 11. Results of Standardization Activities

3. Human Interface

Study of the human interface is intended to bring about wider application of AHS results, wider knowledge of AHS effectiveness, and greater utilization of these systems. To that end, our primary objective is to facilitate earlier familiarity with the nature of AHS. We also intend to provide a certain minimum level of service to existing vehicles that do not have on-board equipment. At present, we are studying the interface consisting of roadside display boards, as well as other interfaces, by means of both hypothetical, desktop tests and road tests. We hope to incorporate our findings in the tests scheduled for next year. (Fig. 12, Fig. 13.)

Fig. 12. Human Interface Research

Fig. 13. Results of Human Interface Research

One issue is clarification of the role of roadside displays. Vehicles equipped with AHS functions also have their own on-board display and interface. Given this, the first step must be to determine the precise role of roadside displays. Large display boards are difficult to place in intersections, so the question about their role for information provision in intersection systems is especially acute, and the choice of interfaces is a major issue. (Fig. 14.)

Fig. 14. Future Issues for the Human Interface

Fig. 15 shows the organization of principal AHS user services. The direction and systems sought for AHS were formulated in 1997. Our efforts up to the present have placed priority on the improvement of safety as set forth in this system. Given the traffic problems existing in Japan, however, there is no doubt that there are also great expectations for improvement of efficiency and the environment, and further for the convenience and comfort required in an aging society. This is not to suggest that progress has been sufficient, but at least the work on safety has made a good start. At the same time that we proceed with further enhancement of safety, we also hope to initiate studies of how to realize the AHS potential for improvement in the areas of efficiency, the environment, and comfort. (Fig. 15.)

Fig. 15. Configuration of AHS Principal User Services

One example of such activity is the AHS infrastructure forum, which was initiated in April of this year. Its purpose is to review and propose policies for the construction of road infrastructure in order to utilize AHS technology as a means for making significant strides toward resolution of the various problems experienced by road traffic. We intend to clarify and define the services and issues involved, and in order to achieve earlier results, we plan to submit a proposal that incorporates practically feasible services in about five years. We also intend to formulate an action plan for research and development. During the coming two-year period, AHSRA will bear the burden of facilitating the practical application of safety-related systems. For us, however, this does not mean that there is nothing for us to accomplish in AHS beyond that point. Therefore we feel it necessary to study this action plan that extends into the period beyond that. In concrete terms, we will proceed by meeting once every month and carrying on exchanges with related organizations. The first half of fiscal 2001 will be devoted to formulating problems and reviewing research topics. In the second half, we hope to narrow our focus to certain topics. We hope to receive proposals and statements of problems from a variety of quarters, and to carry on discussions with them. Therefore, we hope that our readers may become interested and submit proposals or take part in other ways. (Fig. 16.)

Fig. 16. AHS Infrastructure Forum