Handbook for designing roadways for the aging population.

Brewer, Marcus; Murillo, Debbie; Pate, Alan · 2014 · ROSA P / United States. Department of Transportation. Federal Highway Administration. Office of Safety

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Summary

This document, the *Handbook for Designing Roadways for the Aging Population*, addresses the critical need to adapt highway infrastructure to accommodate the rapidly growing demographic of older adults in the United States. Motivated by projections that the population aged 65 and over will exceed 55 million by 2020 and account for roughly one-fifth of driving-age individuals by 2030, the handbook responds to age-related declines in vision, flexibility, psychomotor performance, and cognitive processing. These physiological changes increase crash risks and reduce mobility independence, necessitating design practices that explicitly recognize these limitations to ensure safety for both drivers and pedestrians. The handbook serves as a practical guide for highway designers, traffic engineers, and safety specialists, supplementing existing standards such as the *Manual on Uniform Traffic Control Devices* (MUTCD) and the *Green Book*. It is structured into two main parts: Part I presents specific design treatments, while Part II provides the rationale and supporting evidence. The content is organized around five categories of roadway features: intersections, interchanges, roadway segments, construction/work zones, and highway-rail grade crossings. Within these categories, the handbook details 51 proven and promising treatments, alongside 18 "Promising Practices" identified through subjective assessment by development staff. Each treatment includes specific recommendations, illustrative figures, and relationship codes that link the guidance to existing design manuals, indicating whether the recommendation selects conservative values, resolves discrepancies, or extends current practices. Key findings and recommendations focus on mitigating specific deficits associated with normal aging. For intersections, which represent the highest crash risk for older users, treatments include optimizing intersecting angles, widening receiving lanes, improving sight distance, and enhancing signage visibility through larger letter heights and high-visibility crosswalks. For interchanges, the handbook addresses difficulties with merging and lane changing by recommending improved exit signage, delineation, and acceleration/deceleration lane designs. Roadway segment treatments emphasize curve warning markings, high-friction surface treatments, and road diets to reduce steering demands and workload. Construction zone guidance focuses on increased advance warning and channelization to manage unexpected events. Highway-rail grade crossing recommendations prioritize lighting and passive traffic control devices to aid detection. The handbook explicitly excludes treatments for conditions like Alzheimer’s disease or drowsiness, focusing instead on normally aging users. The significance of this handbook lies in its role as a proactive tool for enhancing transportation safety and mobility. It enables practitioners to implement treatments preemptively during the design of new facilities or as remedial measures at crash sites. By linking human factors research to specific engineering solutions, the handbook supports the creation of roadways that are safer for aging users and, by extension, all road users. It emphasizes that while these treatments do not constitute mandatory standards, their implementation can yield substantial gains in safety and operational efficiency, reducing the whole-life cost of projects by minimizing the need for post-construction remedial works.

Key finding

The handbook provides a comprehensive set of design treatments for intersections, interchanges, roadway segments, construction zones, and rail crossings to address the specific safety needs of the aging population.

Methodology

review

Provenance

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

Topics

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• roadway lighting effects
• perceptual countermeasures
• rail grade crossings
• sign visibility legibility
• signage environment
• age related perceptual decline