Lane-Change Response to Infrastructure Warning About Lane Closure in a Mixed Vehicle Fleet

Svancara, Austin; Calvo, Jose; Chao, Szu-Fu; Lee, Yi-Ching; Jannat, Mafruhatul; Eisert, Jesse · 2025 · ROSA P / United States. Federal Highway Administration. Office of Safety and Operations Research and Development

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Summary

This study investigates driver responses to infrastructure warnings about lane closures in a mixed vehicle fleet comprising both conventional and automated vehicles. The research addresses the challenge of "information mismatch," where Automated Driving Systems (ADS) may fail to interpret non-standardized Changeable Message Signs (CMS), potentially leading to safety issues or driver mistrust. The authors examine whether Cooperative Driving Automation (CDA)—which transmits infrastructure data directly to vehicles—can improve driver behavior and system integration when combined with or replacing traditional CMS. The researchers conducted a driving simulator experiment with 96 participants using a 2x3x2 between-subjects design. The factors manipulated were vehicle automation (none vs. simulated SAE Level 3 automation), message source (CMS only, CDA alert only, or both), and message type (instructional vs. informational). Participants navigated a scenario involving a traffic incident requiring a lane change. The study measured driving metrics, including lane-change timing, distance, steering variability, and speed, as well as eye-tracking data and post-drive questionnaires regarding trust and awareness. Results indicated that drivers receiving both CDA alerts and CMS messages executed "smoother" lane changes, characterized by longer maneuver times, greater distances traveled, and reduced steering wheel angle variability compared to those receiving only CMS information. Drivers equipped with simulated Level 3 automation displayed "less smooth" maneuvers, with shorter times and higher steering variability. Notably, 65% of drivers with L3 automation disengaged the system just before or during the lane change. Regarding message content, drivers exposed to informational messages initiated lane changes sooner after passing the CMS than those who received instructional messages. The study also observed significant interaction effects among automation level, message source, and message type. The findings suggest that integrating CDA alerts with traditional CMS improves the smoothness and safety of lane-change maneuvers in mixed fleets. The research supports the deployment of CDA technology to bridge the information gap between infrastructure and automated vehicles. By providing redundant or direct messaging, CDA can mitigate the risks associated with ADS misinterpretation of variable signage and enhance driver trust. These results provide transportation agencies with evidence to justify the investment in CDA-equipped infrastructure to support the safe integration of automated vehicles into existing road networks.

Key finding

Drivers who received lane closure warnings from both a changeable message sign and an in-vehicle cooperative driving automation alert displayed smoother lane changes with less steering variability than drivers who received warnings from the sign alone.

Methodology

simulator

Sample size: 96

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via bulk_ingest_rosap on 2026-05-23 (6 acquisition events logged).

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

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• automation surprise
• situational awareness
• work zones
• lane changing
• odd communication
• traffic density

Information type

What kind of knowledge this paper contributes, grouped by family — independent of topic (what it is about) and method (how it was studied).

• Empirical Findings: behavioral performance data
• Methodological Resource: tool software
• Theoretical Contribution: conceptual framework