Desk Reference to the Handbook for Designing Roadways for the Aging Population

Brewer, Marcus A.; Bedsole, Lisa · 2015 · ROSA P / United States. Department of Transportation. Federal Highway Administration. Office of Safety

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 document serves as a companion "Desk Reference" to the third edition of the Federal Highway Administration’s (FHWA) *Handbook for Designing Roadways for the Aging Population*. Published in 2015, the reference guide addresses the need for roadway designs that accommodate the functional declines associated with normal aging, such as reduced vision, slower decision-making, and diminished physical ability. The primary motivation is to improve safety for aging drivers and pedestrians by providing practitioners with a condensed, field-ready summary of design treatments that mitigate crash risks and enhance usability for this demographic. The document organizes recommendations into five categories: intersections, interchanges, roadway segments, construction/work zones, and highway-rail grade crossings. It distinguishes between "Proven Practices," which are supported by research, and "Promising Practices," which are subjectively assessed as beneficial by agency staff. The guide provides a three-step implementation procedure for engineers: identifying problems through crash data and demographic analysis, selecting appropriate design elements, and making implementation decisions based on engineering judgment. Specific technical recommendations include geometric adjustments, such as maintaining intersection angles of 90 degrees (or no less than 75 degrees if right-of-way is restricted) and using positive offsets for left-turn lanes to improve sight distance. It also specifies operational changes, such as using an 8.0-second gap value plus 0.5 seconds per additional lane for intersection sight distance calculations to account for slower aging driver maneuvers. Key findings and recommendations emphasize high-visibility treatments and simplified geometry. For channelization, the document recommends raised sloping curbs over pavement markings alone for roadways with operating speeds under 45 mph, accompanied by retroreflective markings with a minimum luminance contrast of 2.0 (with lighting) or 3.0 (without lighting). For offset left-turn lanes, it advises using larger sign sizes, prismatic retroreflective sheeting, and retroreflective pavement markings to reduce wrong-way maneuvers. The guide also advocates for median channelization with continuous raised curbs instead of two-way left-turn lanes in high-volume areas to reduce midblock conflicts. These treatments are illustrated with figures and cross-referenced to the full Handbook for detailed rationale and supporting evidence. The significance of this Desk Reference lies in its practical application for transportation engineers and planners. By providing a streamlined, accessible format of the comprehensive Handbook, it facilitates the integration of age-friendly design principles into both new construction and existing roadway modifications. The document underscores that these enhancements benefit all road users while specifically addressing the disproportionate risks faced by aging populations. It encourages proactive design strategies to minimize crash severity and reduce the long-term costs associated with remedial works, thereby promoting a safer transportation system for an increasingly aging demographic.

Key finding

The Desk Reference provides a structured set of proven and promising design treatments for intersections, interchanges, roadway segments, work zones, and rail crossings to enhance safety for aging road users.

Methodology

review

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.

• perceptual countermeasures
• signage environment
• roadway lighting effects
• sign visibility legibility
• road geometry
• intersection design

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).

• Applied Guidance: design guidelines