Exploration of the SHRP2 naturalistic driving study data to identify factors related to the selection of freeway ramp design speed.
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Summary
This report explores the feasibility of using the Strategic Highway Research Program 2 (SHRP2) Naturalistic Driving Study (NDS) database to identify freeway entrance and exit ramps and analyze driver behavior, particularly among teens, on these facilities. The research was conducted in preparation for National Cooperative Highway Research Project (NCHRP) 15-56, which aims to review and potentially revise current practices for selecting freeway ramp design speeds. The primary objective was to determine if the NDS dataset could serve as a tool for study site selection based on roadway characteristics and provide a data source for validating field data or analyzing the relationship between design speed, vehicle performance, and driver behavior. The researchers conducted a comprehensive review of the NDS database structure, examining 1,156 variables across 21 data dictionaries and seven components of the associated Roadway Information Database (RID). They assessed the potential of variables in the Vehicles, Drivers, Trips, and Events datasets to identify ramp locations and relevant geometric or behavioral data. To test the practical utility of the database for this specific purpose, the team performed a query of the NDS database to identify all crash, near-crash, and crash-relevant events that potentially occurred on ramps. This initial query identified 939 events from 917 trips that met the search parameters. Upon detailed review of the records from the 939 identified events, the researchers found that only 49 events actually occurred on a freeway ramp. Of these 49 events, 48 were categorized as near-crashes, and one was a crash involving a subject driver driving over road debris. The low yield of ramp-specific events in the publicly accessible or initially queried data highlighted significant limitations in using the standard NDS interface for this specific research question. The review indicated that while the dataset contains extensive information on driver demographics, vehicle conditions, and trip summaries, the available variables through the InSight website were insufficient for directly identifying ramp locations or analyzing detailed behavior on ramps without further data acquisition. The study concludes that further exploration of the relationship between design speed and driver behavior on freeway ramps requires access to more detailed datasets that must be purchased from NDS project administrators. The current exploration suggests that the NDS database has potential as a supplementary resource for future research, particularly for validating field data or studying teen driver behavior, but it cannot currently serve as a standalone basis for analyzing ramp design speed factors without acquiring the full, detailed time-series data. The report recommends that future tasks under NCHRP 15-56 consider purchasing these detailed datasets to enable precise identification of ramp segments and corresponding driver actions.
Key finding
Only 49 out of 939 potentially ramp-related events in the SHRP2 NDS database were confirmed to have occurred on freeway ramps, indicating the publicly available data is insufficient for detailed ramp design speed analysis.
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 (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.
- naturalistic crash near crash
- incidence prevalence
- speed choice
- perceptual countermeasures
- urban rural setting
- rail grade crossings
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, observational prevalence
- Methodological Resource: dataset resource