Developing Smart Signs for Traffic Control in Work Zones [Summary]

Sandberg, Wayne; Morris, Nichole · 2023 · ROSA P / Minnesota. Department of Transportation. Office of Research & Innovation

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Summary

This research addresses the high safety risks associated with work zone traffic control, where flaggers serve as the primary defense against distracted or aggressive motorists. While digital smart signs have been tested to alert drivers and warn workers of unsafe vehicle intrusions, previous iterations suffered from operational complexity, cumbersome size, and prohibitive costs. Motivated by Minnesota’s “Toward Zero Deaths” goal, the study aimed to develop an affordable, portable intrusion detection system capable of electronically monitoring approaching vehicles to warn both drivers and workers of potential threats. The project employed a user-centered design approach, incorporating feedback from roadway maintenance employees to refine the system’s functionality and usability. The initial prototype was a modified Stop/Slow paddle equipped with low-cost radar sensors, an embedded microprocessor, and algorithms to track vehicle trajectory and predict intrusions. This unit included an audiovisual warning system and a camera, mounted on a rolling platform for mobility. Based on worker feedback regarding visibility and safety distance, the design was revised to a remote-controlled traffic signal displaying standard red, yellow, and flashing yellow indications. Both prototypes underwent rigorous usability testing in a driving simulator with 36 participants, who navigated scenarios involving either a traditional flagger or the prototype systems. Researchers assessed driver stopping behavior, system acceptance, and the efficacy of the trajectory tracking algorithms. The results indicated that drivers exhibited significantly more stop failures and late stops when interacting with the prototype traffic signal compared to a traditional flagger. Although drivers perceived the signal as having greater visibility and authority, it did not yield safer driving performance. In contrast, a modified Stop/Slow paddle featuring a flashing red LED border and an auditory alarm outperformed the traffic signal. Drivers using this enhanced paddle demonstrated improved stopping behavior and were less likely to fail to remain stopped. Nearly all participants fully complied with the modified flagger system. Additionally, the vehicle trajectory tracking system successfully identified all intruding test vehicles and provided appropriate warnings in both configurations. The study concludes that the modified Stop/Slow paddle with audiovisual alerts promotes the safest driving performance and highest compliance, surpassing the remote-controlled traffic signal prototype. These findings highlight the importance of integrating worker feedback into system design to ensure acceptance and efficacy. The research supports the continued role of flaggers while enhancing their safety through technology. Future work includes a pilot study to further modify the paddle system for remote operation, assess road worker acceptance, and validate whether simulation results translate to real-world settings. This project represents a significant step toward developing cost-effective, user-centered smart traffic control systems that mitigate driver distraction and protect work zone personnel.

Key finding

A modified Stop/Slow flagger paddle equipped with an LED border and auditory alarm outperformed a prototype traffic signal in promoting safe driver stopping behavior and achieving high compliance in simulated work zones.

Methodology

simulator

Sample size: 36

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

Ranked by relevance to this paper. Hover a topic for its definition.

• emergency work zone conspicuity
• work zones
• vru facing ehmi