Association of Michigan’s older adult crashes with roadway features : final report.
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Summary
This study addresses the safety challenges faced by older drivers (aged 65 and older) in Michigan, who exhibit higher crash risks per vehicle mile traveled and greater susceptibility to severe injury. Motivated by the need to align Michigan Department of Transportation (MDOT) design standards with the Federal Highway Administration’s 2014 Handbook for Designing Roadways for the Aging Population, the research aims to identify specific roadway features associated with older adult crashes and provide targeted engineering guidance. The methodology combined a comprehensive literature review, a survey of Michigan road users, and a statistical analysis of crash data from 2010 to 2014. The survey gathered perspectives from drivers regarding transportation alternatives and specific driving concerns, comparing older adults to those aged 64 and younger. The crash analysis utilized two primary approaches: a general distribution analysis of all crashes and an in-depth examination of two-vehicle crashes involving one older and one younger driver. This latter method controlled for exposure by identifying roadway features where older drivers committed hazardous actions more than 50% of the time, indicating specific design vulnerabilities. Key findings revealed that older drivers disproportionately avoid driving at night, in bad weather, and during left turns. Crash data confirmed that intersections were the most problematic locations, with older drivers responsible for hazardous actions in 54% of intersection crashes compared to 46% for younger drivers. Specific design features significantly influenced safety outcomes. Older drivers were less likely to be at fault at intersections with raised medians (52% vs. 59% without) or offset left-turn lanes (55% vs. 58% without). Conversely, skewed intersections with small angles increased older driver responsibility, particularly at stop-controlled intersections. Lighting also played a critical role; older drivers were less responsible for crashes at lighted rural intersections compared to unlighted ones. Additionally, older drivers showed higher involvement in crashes at driveways away from intersections and median crossovers, often due to failure to yield. The study concludes with specific recommendations for enhancing MDOT’s roadway design guidance to improve safety for aging populations. It identifies opportunities to adopt countermeasures such as optimizing intersection skew angles, implementing right-turn channelization, ensuring adequate intersection sight distances, and using positive offset left-turn lanes. The report also includes a benefit-cost analysis of these potential countermeasures, providing MDOT with evidence-based strategies to reduce crash involvement and severity for older drivers through improved infrastructure design.
Key finding
Older drivers were more likely to commit hazardous actions causing crashes at intersections, particularly at stop-controlled and skewed intersections, but were less likely to be responsible for crashes at intersections with raised medians or adequate lighting.
Methodology
mixed_methods
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).
| Stage | Outcome | Tool | Model | Prompt | Attempts | Completed |
|---|---|---|---|---|---|---|
| discover | success | rosap | — | — | 2 | 2026-05-23 |
| archive | success | — | — | — | 1 | 2026-05-23 |
| extract | success | cached | — | — | 2 | 2026-06-10 |
| clean | success | — | — | — | 1 | 2026-06-01 |
| chunk | success | — | — | — | 1 | 2026-06-01 |
| embed | success | — | — | — | 1 | 2026-06-02 |
| enrich | success | — | — | — | 1 | 2026-05-23 |
| promote | success | — | — | — | 1 | 2026-05-23 |
| summarize | success | llm | qwen3.6-27b-prismaquant | summ-v5 | 3 | 2026-06-10 |
| tag | success | vector_similarity | — | — | 19 | 2026-06-11 |
| verify | success | — | — | — | 2 | 2026-06-10 |
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.
- roadway lighting effects
- older drivers
- rail grade crossings
- pedal misapplication
- incidence prevalence
- urban rural setting
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).
- Empirical Findings: crash risk outcomes
- Methodological Resource: dataset resource