Summary

Congestion mitigation remains a big challenge in California. Several tools are under investigation and development in order to contain and/or reduce congestion. These tools usually address traffic management solutions or driver information. Another venue to address is driver behavior itself, through the implementation of systems assisting drivers and allowing them to practice smoother and better control of their vehicle. An example of such a system is the Adaptive Cruise Control (ACC), and its next generation, the Cooperative Adaptive Cruise Control (CACC). ACC systems are now available at the production level but their market penetration remains confined to the upper level of the passenger car market. CACC are still at the prototype level. Therefore, the best tool to evaluate their impact on traffic flow has been simulation. These simulations indicate that ACC and CACC might be valuable tools in order to mitigate congestion and increase safety on highways. However, simulations rely on assumptions about driver behavior and use of the system, especially in terms of the gap drivers will be willing to practice with the system. Consequently, necessary steps for strengthening the simulation consist in collecting data on driver behavior while using ACC and CACC, and integrating the resulting insight into the simulation. The simulation can then be used to provide authoritative predictions of the effects that ACC and CACC are likely to have on traffic flow (especially highway capacity) when they are widely deployed.

We envision a two years and a half year research plan. The focus of the first year will be the development, in partnership with Nissan, of a CACC system. This development will be based on the Nissan ACC currently commercialized on their Infinity FX45. At the end of this task, two Infinity FX45s vehicles will be equipped with a CACC and instrumented for data collection. The focus of the second year will be on the data collection. For this purpose, a group of volunteer drivers will be constituted based on age and gender criteria. Each of the drivers will be using one of the Nissan vehicles as their own vehicle for a familiarization period. During this phase, drivers will be using the ACC available on the vehicle at their own convenience. At the end of this period, drivers will fill out questionnaires and participate in an interview. Then, they will learn how to use the CACC and a test drive will be conducted with the experimenter on-board. The data collected will then be used for the last effort involved in this research plan, the simulation. This simulation will integrate time-gap selected by drivers and also drivers' intervention while using the system. The simulation will comprise collaboration with the Netherlands Organization for Applied Scientific Research (TNO), which will allow for a comparison of the simulations run in each institution.

To summarize, this project will be constituted of three main tasks and two milestones. The first milestone will be the completion of the equipped vehicles and the second will be the completion of the data collection and processing. The end of the simulation task will coincide with the end of the project. The final report will describe the CACC system implemented, the protocol and results of the data collection, and the results of the simulation. The results of this simulation will support decision makers in evaluating the effectiveness of CACC for congestion mitigation and safety enhancement. This is important for decision about whether to provide public incentives for use of the systems, such as priority access to High Occupancy Vehicle (HOV) and High Occupancy Toll (HOT) lanes. The collected data will support other research in California concerning driver behavior and the technologies implemented for this system, e.g. the vehicle-to-vehicle communication.