Safety and driver behavior studies at multiple lane approaches to stop-controlled intersections.
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Summary
This study investigates the safety and driver behavior at multiple-lane approaches (MLAs) to two-way stop-controlled intersections, a configuration increasingly common in Nebraska when single-lane approaches cannot handle traffic volume but signal warrants are not met. The primary motivation was to address potential safety hazards caused by sight distance obstructions, where vehicles stopped side-by-side at stop signs block each other’s view of major road traffic. The research aimed to determine if MLA intersections exhibit different crash frequencies and rates compared to single-lane approaches (SLAs) and signalized intersections, and to evaluate driver compliance with positioning guidelines. The methodology involved two main components: a safety analysis using crash data and a driver behavior study using field observations. For the safety aspect, the researchers analyzed crash data from 40 MLA intersections in Nebraska. They employed Empirical Bayes comparison-group methods to assess before-after changes at four intersections that were converted to either signal control or SLA configurations. Additionally, a 3-factor Analysis of Variance (ANOVA) was used to compare 3-year average crash rates of MLA intersections against SLA and signalized intersections, categorized by geometric factors such as the number of legs, major road lanes, and speed limits. The driver behavior component utilized video recordings and field studies to measure vehicle positioning relative to staggered stop bars and to test the effectiveness of visual cues, including "STOP AT LINE" signs. The safety analysis revealed that while signalization of MLA intersections resulted in improved safety, the difference was not statistically significant at the 95 percent confidence level. Converting an MLA to an SLA reduced crash frequency, yet the MLA configuration demonstrated a statistically significant lower average crash rate than the SLA at the 95 percent confidence level, though the conversion increased driver delay. Crash rate comparisons indicated that MLA intersections on 2-lane major roads had higher-than-average crash rates when horizontal curves were present near the intersection. Similarly, MLA intersections on 4-lane major roads in urban areas exhibited higher-than-average crash rates. Driver behavior studies showed inconsistent compliance with staggered stop bars, highlighting the need for clearer visual guidance. The study concludes that MLA intersections should be used with caution, particularly on 4-lane urban roadways and locations with nearby horizontal curves. To mitigate safety risks, the authors recommend providing consistent, redundant positive visual guidance to ensure right-turning drivers position themselves ahead of left-turning drivers. Specific recommendations include developing a combined text and iconic "STOP AT LINE" sign, updating the Nebraska Driver’s Manual to clarify proper stopping positions at painted stop bars, and conducting further before-after field studies to quantify the effectiveness of these proposed improvements.
Key finding
Converting a multiple-lane approach to a single-lane approach significantly reduced crash frequency, whereas the multiple-lane configuration maintained a statistically significant higher average crash rate compared to single-lane intersections.
Methodology
field_study
Sample size: 40
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
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- intersection design
- roadway lighting effects
- rail grade crossings
- perceptual countermeasures
- regulatory evaluation
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