Right-Turn Decision Support Based on Dynamic Gap Distribution Prediction at Multi-Lane Intersections

Haru Ishizuki･Hiroyuki Okuda (Nagoya University)･Takuma Yamaguchi･Kazunori Ban (Toyota Technical Development)･Heishiro Toyoda (Toyota Motor)･Tatsuya Suzuki (Nagoya University)

This study proposes a right-turn decision support system for multi-lane intersections that utilizes wide-area infrastructure sensor data to account for the lane-changing behavior of oncoming vehicles. The system dynamically and probabilistically predicts the gap distribution caused by lane changes, and supports optimal decision-making to maximize the driver's expected utility by balancing the trade-off between safety margins and waiting time.

Brake Operation Characteristic Design Considering Ankle Joint Passive Resistance for Full Brake by Wire Systems

Tomohiro Yokoyama･Kengo Ito･Shotaro Kaga (Toyota Motor)･Hiroshi Yoshitake･Motoki Shino (Institute of Science Tokyo)

In conventional hydraulic brake systems, pedal stroke is structurally constrained because the system is designed based on the fluid volume and master cylinder stroke required to reliably generate braking force. As a result, brake pedal characteristics have traditionally been optimized with priority given to hydraulic feasibility, making it difficult to freely design the pedal operation system based on human operation characteristics. In contrast, the application of brake-by-wire (BbW) technology mechanically decouples pedal operation from brake force generation, allowing system design to be freed from fluid-volume and mechanical constraints. This enables new possibilities for designing brake operation systems based on human characteristics. With BbW technology, the relationship between pedal force (Force), pedal stroke (Stroke), and vehicle deceleration (G), namely the F-S-G characteristics, is no longer restricted by mechanical constraints, resulting in a significant increase in design freedom. This has made it possible to design a wide range of brake operation characteristics with an emphasis on pedal feel and reduction of driver workload. For example, not only pedal reaction force but also pedal stroke itself can now be treated as a design variable, enabling the reconstruction of operation styles that were difficult to realize under conventional hydraulic constraints. Consequently, brake operation systems that better match human movement characteristics—such as operation based on heel support utilizing the natural rotational motion of the ankle joint—can be considered feasible. On the other hand, the design of F-S-G characteristics still relies heavily on subjective driving evaluations and empirical tuning, and systematic design guidelines grounded in human characteristics have not yet been sufficiently established. Previous studies have focused on ankle-dominant braking behavior and have shown that, in muscle-driven control regions where the soleus muscle acts as the primary contributor, the relationship between operation input and perceived deceleration can be approximated by the Weber–Fechner law. However, vehicle evaluations and subjective assessments have also confirmed that pedal force is generated even under relaxed conditions and that this force significantly influences the initial brake pedal feel. Such initial operation characteristics have not been clearly theorized under conventional design concepts based on fluid volume and stroke constraints. In this study, the origin of the pedal force generated under relaxed conditions is redefined as joint passive resistance at the ankle joint, and a brake operation characteristic design method that explicitly incorporates this effect into the F-S-G characteristics is proposed.

A Study on Enhancing Driver Situational Awareness Using Seat Haptic Stimuli via Multi-Vibrator Configurations

Yukiyo Kuriyagawa (Nihon University)･Hidefumi Koizumi･Shinichi Sagawai･Hirosh Wakuda･Toshiki Nakamura･Keigo Abe･Kunio Sato (Alps Alpine)

運転者⽤シート振動による触覚刺激を視聴覚刺激の代替やこれらと組み合わせて⽤いることで, 快適で直感的な運転⽀援効果を得ることを⽬指している．本研究では, シート内の複数振動子を組み合わせることで, ドライバの車両周辺等への状況認識向上効果を図った検討結果を述べる．

Theory of Personalized HMI Design for Promoting Safe Driving Using Structural Equation Modeling

Kaito Murotani･Keisuke Suzuki (Kagawa University)･Emiko Yoshida (Aioi Nissay Dowa Insurance)

Based on one-week real-world driving data and surveys of individual characteristics, this study proposes an information-presentation HMI design methodology that integrates latent psychological factors (personality) with manifest factors (driving behavior). We enhanced the reliability of the presented information by visualizing causal structures via Structural Equation Modeling (SEM), thereby employing a transparent logic distinct from black-box AI. By delivering warnings optimally tailored to individual drivers, this novel design paradigm effectively achieves both user trust-building and safe driving, establishing a vital framework for the approaching Software-Defined Vehicle (SDV) era.

Structure of Model to Quantify Psychological Aspects of Tactile Feedback to Switches

Hideki Sakamoto (Alps Alpine)･Hyoungsun Kim (Tohoku University)･Syota Takeuchi (Alps Alpine)･Wenyu Zhang･Chunlin Liu･Yi Ding (Tohoku University)･Hisato Shimomura･Kunio Sato (Alps Alpine)･Motoaki Sugiura (Tohoku University)

Switches installed in automotive cockpits are required to provide various operational tactile sensations depending on their intended functions. Although subjective evaluation has been used to assess these tactile sensations, it is well known that the evaluation items representing psychological quantities exhibit large inter-subject variability, making objective assessment difficult. This study aimed to clarify the sensory dimensions of tactile experiences by identifying their neural representations in the brain using fMRI, and to establish an objective evaluation method based on neural indices.

Structure of Model to Quantify Psychological Aspects of Tactile Feedback of Switches (Third Report)

Yuya Nanaeda･Hideki Sakamoto (Alps Alpine)･Shoichiro Takehara (Sophia University)

Switches equipped in the cabin of automobiles require various tactile feedbacks depending on their purposes for each user. In this study, we identified the factors that classify individual preferences by analysis based on subjective evaluation results of tactile feedbacks when pressing a switch. In addition, we constructed models which showed correlation between psychological quantity and mechanical properties for each evaluator group categorized by attributes.

A Study on a Quantitative Evaluation Method for Daytime Visibility of Automotive Interior Illumination Using CIELAB

Seong Uk Kim (Hyundai Motor)

Daytime visibility assessment of automotive interior illumination has traditionally relied on subjective evaluation, leading to inconsistent pass or fail criteria. This study proposes a quantitative method based on LMK imaging photometer measurements in CIELAB color space. Although dE00, a conventional color difference metric, did not correlate well with visual perception, dLstar and LCR were found to be more effective indicators of daytime visibility. Empirical analysis showed that daytime visibility was insufficient when dLstar was below 4.5 or LCR was below 0.06. This luminance based criterion enables objective and reproducible evaluation for automotive interior illumination design.