Effectiveness of various safety improvements in reducing crashes on Wyoming roadways.
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Summary
This study evaluates the effectiveness of the Wyoming State Highway Safety Plan (WSHSP) and specific safety countermeasures in reducing the severity of roadway departure crashes on Wyoming’s rural roadways. Motivated by the high societal costs of crashes and the Federal Highway Administration’s mandate for Safety Management Systems, the research focuses on roadway departures, which accounted for 37% of serious injury and fatal crashes in Wyoming in 2004. The primary objectives were to determine the impact of geometric conditions on crash severity, evaluate the overall effectiveness of the 2006 WSHSP, and assess the performance of two specific safety devices: shoulder rumble strips (SRS) and cable median barriers. The researchers utilized crash data from the CARE 9 database to conduct before-after analyses. The study examined eight combinations of geometric conditions across rural interstates, state highways, and local roads. For the safety devices, the analysis compared crash frequencies and severity before and after installation. SRS effectiveness was evaluated using one-tailed t-tests on severity and run-off-road (ROR) crash types per mile, separating interstate and state highway data due to traffic volume differences. Cable median barrier effectiveness was assessed using crash numbers from a two-year before-after period for five projects installed between 2007 and 2008. The analysis focused on crash frequencies rather than rates, consistent with WSHSP methodology and due to unreliable million vehicle miles traveled data for local roads. The results indicated that the implementation of the WSHSP contributed to a considerable reduction in fatal and serious injury crashes statewide. Geometric analysis identified curve-downhill and curve-level sections on state highways and local roads as the most severe crash locations, with rollovers being the most frequent and severe roadway departure crash type. Statistical analysis of SRS installations showed a significant reduction in crash severity on both interstate and state highway sections. The cable median barrier analysis revealed a large reduction in fatal and serious injury crashes on interstate sections. This reduction translated to an estimated annual societal savings of approximately $322,000 per mile of installed cable median barrier. The study concludes that cost-effective safety improvements, specifically SRS and cable median barriers, are effective in reducing the severity of roadway departure crashes in Wyoming. The findings support the proactive identification of hazardous geometric conditions and the targeted installation of safety devices. The research demonstrates that even on roadways with relatively low traffic volumes, such safety measures yield significant benefits in terms of crash severity reduction and societal cost savings, validating the strategies outlined in the WSHSP.
Key finding
Shoulder rumble strips significantly reduced run-off-road crash severity on interstate and state highways, while cable median barriers reduced fatal and serious injury crashes with an estimated annual savings of $322,000 per mile.
Methodology
dataset
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 (7 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 | — | — | 20 | 2026-06-11 |
| verify | success | — | — | — | 2 | 2026-06-10 |
Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.
Topics
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- incidence prevalence
- perceptual countermeasures
- roadway lighting effects
- adas effectiveness
- comparative international
Information type
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- Empirical Findings: crash risk outcomes