Symbol Signing Design for Older Drivers

Dewar, Robert; Kline, Donald; Scheiber, Frank; Swanson, Alan · 1997 · ROSA P / United States. Federal Highway Administration

archive: archived pipeline: cataloged verified

Get this paper ↗ (full text — opens at the source; we link to it, we don't host it)

Summary

This report addresses the critical need to evaluate and improve the effectiveness of symbol traffic signs for older drivers, a demographic whose numbers and driving participation are rapidly increasing. The research was motivated by evidence that accident rates rise for drivers over age 55, often due to failures in detecting, reading, or understanding traffic signs. While symbols offer advantages such as faster identification and language independence, many existing symbols in the U.S. Manual on Uniform Traffic Control Devices (MUTCD) are poorly understood or difficult to recognize at a distance, particularly by older adults. The study aimed to systematically assess the effectiveness of standard symbols, develop improved designs, and establish design guidelines that accommodate the sensory and cognitive limitations associated with aging. The research employed a two-phase experimental design involving male and female licensed drivers categorized into young (18–39), middle-aged (40–59), and older (60+) groups. Phase 1 evaluated 85 standard MUTCD symbols for daytime legibility distance and comprehension. Based on these results, 18 symbols representing the best, intermediate, and worst performers were selected for further testing. Phase 2 involved laboratory experiments measuring nighttime legibility (with and without peripheral glare), glance legibility, reaction time, and conspicuity for these 18 symbols. Additionally, 13 symbols were modified or redesigned, and five novel symbols were created using an iterative image-processing approach. These new designs were then tested for comprehension and legibility under daytime, nighttime, and glare conditions. The findings revealed that older drivers exhibited significantly poorer comprehension, shorter legibility distances, higher glance legibility thresholds, longer reaction times, and increased conspicuity search times compared to younger drivers. Notably, peripheral glare reduced sign legibility exclusively for older drivers. Among the 85 standard symbols evaluated, 10 were understood by fewer than 40% of drivers. The redesign efforts yielded positive results: modifications improved the understanding of three specific messages and increased the daytime legibility distance for 11 of the new designs. Furthermore, the five novel symbols developed for the project demonstrated comprehension and legibility levels comparable to the redesigned standard symbols. The significance of this work lies in its comprehensive evaluation of symbol effectiveness across multiple human factors metrics, filling a gap in previous research that often examined only single variables. The report provides specific recommendations for modifying problematic standard symbols and proposes detailed guidelines for future symbol design. These guidelines emphasize consistency, clarity, and the accommodation of age-related visual declines, such as reduced contrast sensitivity. The authors also advocate for the use of computer-based design optimization techniques in the development and evaluation of traffic signs to ensure they remain effective for an aging driving population.

Key finding

Older drivers exhibited poorer symbol comprehension, shorter legibility distances, and slower reaction times than younger drivers, and peripheral glare reduced sign legibility only for the elderly.

Methodology

lab_experiment

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_with_issues.

Topics

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

• sign visibility legibility
• signage environment
• age related perceptual decline
• sensory abilities
• contrast sensitivity
• disability glare