Impact Speed and a Pedestrian’s Risk of Severe Injury or Death
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Summary
This study addresses the critical relationship between vehicle impact speed and the risk of severe injury or death for pedestrians in the United States. Previous research relied on outdated U.S. data or European datasets that did not account for the prevalence of light trucks, vans, and SUVs in the American vehicle fleet. Consequently, existing estimates may not accurately reflect current risks due to changes in vehicle design, pedestrian demographics, and medical care. The objective was to provide updated, generalized risk estimates for pedestrians struck by cars and light trucks using recent U.S. data. The analysis utilized data from the National Automotive Sampling System Pedestrian Crash Data Study (PCDS), covering crashes from 1994 to 1998 involving pedestrians struck by forward-moving cars or light trucks. The final sample included 422 pedestrians aged 15 and older. To correct for the oversampling of severely injured or killed pedestrians in the PCDS, the data were post-stratified and weighted to match national injury severity distributions. Missing data for impact speed and confounding variables were handled using multiple imputation. Multivariable logistic regression was employed to estimate risks, adjusting for pedestrian age, height, weight, body mass index, and vehicle type. Results were standardized to reflect the demographic and vehicle distribution of pedestrians struck in the U.S. between 2007 and 2009. The findings establish specific speed thresholds for injury risk. The average risk of severe injury (Abbreviated Injury Scale score of 4 or higher) reaches 10% at 16 mph, 25% at 23 mph, 50% at 31 mph, 75% at 39 mph, and 90% at 46 mph. The risk of death reaches 10% at 23 mph, 25% at 32 mph, 50% at 42 mph, 75% at 50 mph, and 90% at 58 mph. Risk increases approximately linearly within these ranges. Significant variations exist based on vehicle type and pedestrian age. Pedestrians struck by light trucks face risks equivalent to those struck by cars traveling 6.3 mph faster for severe injury and 4.1 mph faster for death. Older pedestrians are also at higher risk; a 70-year-old struck at a given speed faces similar risks to a 30-year-old struck at speeds 9.3 to 10.4 mph higher. These results provide evidence-based benchmarks for pedestrian safety interventions. The study suggests that limiting traffic speeds to levels below 20 mph significantly reduces the likelihood of severe injury or death. Conversely, areas with higher desired traffic speeds require physical separation of pedestrians and vehicles or advanced vehicle-based safety systems, such as automatic braking. The findings highlight the disproportionate vulnerability of older pedestrians and those struck by larger vehicles, informing targeted safety strategies and urban design policies.
Key finding
For a pedestrian struck by a car or light truck, average risk of death reaches 50% at an impact speed of 42 mph (10% at 23 mph, 90% at 58 mph), while average risk of severe injury reaches 50% at 31 mph.
Methodology
modeling
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_aaa_foundation on 2026-05-23 (8 acquisition events logged).
| Stage | Outcome | Tool | Model | Prompt | Attempts | Completed |
|---|---|---|---|---|---|---|
| discover | success | aaa_foundation | — | — | 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 | pubmed | — | — | 5 | 2026-05-27 |
| promote | success | — | — | — | 1 | 2026-05-23 |
| summarize | success | llm | qwen3.6-27b-prismaquant | summ-v5 | 2 | 2026-06-10 |
| tag | success | vector_similarity | — | — | 18 | 2026-06-11 |
| verify | success | — | — | — | 2 | 2026-06-10 |
Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.
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- Empirical Findings: crash risk outcomes