The Problem:

The system design of intelligent transportation systems consists of two parts: (1) the architecture design of the final system, and (2) the design of the conversion process from current systems to final systems. The design methodologies for both aspects are in their infancy and need more research.

Previous Work:

Most of the previous work focuses on the system architecture of fully automated highway systems. The design of the incremental conversion process from existing transportation systems was studied less intensively.

Approach:

The key concept of our approach to design the incremental conversion process is composed of a number of concurrent integrations as described below:

(1) Integration of transportation, communication, and other infrastructures to minimize investment dedicated to transportation
(2) Integration of developments of system design and enabling component technologies
(3) Integration of technical, social, economical, political, and other aspects
(4) Integration of infrastructure (i.e., roads) and users (i.e., vehicles)
(5) Integration of ITSs in different countries
(6) Integration of different transportation modes such as highways and railways

Our focus is to propose methodology for the incremental conversion process from the current to near- future and far-future transportation systems as shown in Figure 1. The conversion system should be designed to provide benefits to society in each investment period. A simplified example is described below to show the concept of the conversion process design.

In this example, suppose that data processing and communication capabilities will be added to the current transportation systems in two different conversion processes as shown in Figure 2:

Conversion Process #1
• In a short-term, 70% of the processing capability and 20% of the communication capability are deployed.
• In a medium-term, 90% of the processing capability and 40% of the communication are deployed.

Conversion Process #2
• In a short-term, 20% of the processing capability and 70% of the communication capability are deployed.
• In a medium-term, 40% of the processing capability and 90% of the communication are deployed.

Both conversion processes will realize the same final system architecture in a long-term, but Process #1 puts more emphasis on the deployment of the data processing capability in its early stage while Process #2 emphasizes communication capability in the short and medium terms. Suppose that there are three major applications (i.e., A1, A2, and A3) which provide significant benefits to the society and that each application requires the following capabilities:

• A1 requires 60% and 10% of the processing and communication capabilities, respectively.
• A2 requires 80% and 30% of the processing and communication capabilities, respectively.
• A3 requires 90% and 90% of the processing and communication capabilities, respectively.

Under this assumption, A1 and A2 become available in the short and medium terms respectively with Process #1, while Process #2 does not make applications available in the short and medium terms. In this particular example, Process #1 is significantly better although the total investment cost and the final system architecture are identical for both conversion processes. This is a simplified example to show that the conversion process can make an important difference.