Delineation of Hazards for Older Drivers, Volume II: Appendixes

Lerner, Neil D.; Benel, Denise C.R.; Huey, Richard W.; Steinberg, Geoffrey V · 1997 · ROSA P / United States. Department of Transportation. Federal Highway Administration

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Summary

This report, Volume II of "Delineation of Hazards for Older Drivers," serves as a companion to Volume I, providing the methodological appendices and supporting data for a research project sponsored by the Federal Highway Administration. The study addresses the growing proportion of drivers over age 65, who face sensory, perceptual, and cognitive declines that impair their ability to detect and comprehend roadside hazards. Specifically, the research investigates the effectiveness of object markers—devices used to delineate immovable obstructions—focusing on their conspicuity, recognizability, and comprehensibility for older motorists. The project aims to optimize the design of Type 1, Type 2, and Type 3 object markers to reduce confusion with other traffic control devices and improve safety. The research methodology comprised three phases: problem identification, laboratory studies, and field verification. Problem identification experiments assessed current marker performance regarding visibility and meaning. Laboratory experiments evaluated proposed design enhancements, including variations in size, color, shape, placement, and symbology, under both daytime and nighttime conditions. Field studies verified these findings in real-world settings, testing both static markers and active technologies such as flashing beacons. The studies utilized diverse participant groups, including older drivers, and employed measures such as recognition distance, comprehension scores, and confusion rates. Additionally, a cost-benefit analysis was conducted to evaluate the economic viability of adopting new marker designs. The findings indicate that while the specific meanings of current object markers were not always well understood by subjects, the general message of caution or hazard was typically conveyed in field settings. Novel static markers generally yielded higher conspicuity than existing designs, but the magnitude of improvement was small and often not statistically significant. In the cost-benefit analysis, two novel passive markers—the Double Modified Chevron and the cone symbol—demonstrated good results when high weight was placed on conspicuity. Conversely, painted pavement hash marks showed the lowest benefit-cost payoff. Crucially, the additional costs associated with active device applications, such as flashing beacons, were not justified by the cost-benefit analysis. The significance of this research lies in its evidence-based recommendations for highway designers and traffic engineers. The study suggests that while minor design improvements can enhance marker visibility, the adoption of significantly more expensive active devices is not economically justified. The findings support targeted revisions to the Manual on Uniform Traffic Control Devices (MUTCD) to clarify marker meanings and reduce confusion. By identifying which design modifications offer the best balance of safety improvement and cost-effectiveness, the report provides a framework for accommodating the needs of older drivers without imposing unnecessary financial burdens on transportation agencies.

Key finding

Novel object marker designs produced small, generally non-significant improvements in conspicuity, and active devices were not cost-justified compared to existing passive markers.

Methodology

mixed_methods

Sample size: 63

Provenance

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

Topics

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• sign visibility legibility
• signage environment
• rail grade crossings
• external distraction
• hazard perception
• emergency work zone conspicuity

Information type

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• Empirical Findings: behavioral performance data
• Methodological Resource: dataset resource, measurement protocol