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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
REPORT |
This report is an archived publication and may contain dated technical, contact, and link information |
Publication Number: FHWA-HRT-17-016 Date: April 2017 |
Publication Number: FHWA-HRT-17-016 Date: April 2017 |
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Intersections, particularly stop-controlled intersections in rural areas, provide the setting for a large number of traffic crashes. Factors believed to contribute to these crashes include inadequate surveillance, failure to obey/yield, driver inattention, and speed. In 2005, Congress authorized and funded the second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) with the goals of improving safety for motorists and workers, enabling transportation agencies to improve their infrastructure more quickly, targeting resources and enhancing existing processes, and making the system more reliable for travelers.
This research study examined driver stopping and scanning behavior as they approached and entered rural high-speed intersections, producing actionable insights into transportation safety by leveraging the SHRP2 safety databases. This report details the SHRP2 data acquisition process, exploratory analysis, and results. Use of NDS data represents an important addition to the body of knowledge concerning driver behavior at intersections. Secondary objectives include assessing SHRP2’s ability to address further questions of safety and increasing awareness and understanding of relevant analysis techniques and methods.
Monique R. Evans
Director, Office of Safety
Research and Development
Notice
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Technical Report Documentation Page
1. Report No.
FHWA-HRT-17-016 |
2. Government Accession No. | 3 Recipient's Catalog No. | ||
4. Title and Subtitle
Leveraging the Second Strategic Highway Research Program Naturalistic Driving Study: Examining Driver Behavior When Entering Rural High-Speed Intersections |
5. Report Date April 2017 |
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6. Performing Organization Code | ||||
7. Author(s)
Steven Jackson |
8. Performing Organization Report No.
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9. Performing Organization Name and Address Leidos, Inc. |
10. Work Unit No. (TRAIS) |
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11. Contract or Grant No. | ||||
12. Sponsoring Agency Name and Address
Office of Safety Research and Development |
13. Type of Report and Period Covered
Technical Report |
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14. Sponsoring Agency Code
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15. Supplementary Notes
The Contracting Officer’s Representative was David Yang (HRDS-30), and the Government Task Manager was Michelle Arnold (HRDS-30). |
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16. Abstract
Overall, 40 percent of crashes in the United States occur at intersections; a total of 57 percent of fatalities from 1997–2004 occurred at stop-controlled intersections, of which 61 percent occurred in rural areas. Factors believed to contribute to these incidents include inadequate surveillance, failure to obey/yield, driver inattention, and speed. This study used naturalistic driving data collected under the second Strategic Highway Research Program to explore drivers’ brake and glance patterns on approach to rural high-speed, stop-controlled intersections from the minor route. Brake distance was found to be sufficiently predicted by brake speed (the speed at which the driver was moving upon initial brake activation). At an average brake speed of 61.7 mi/h, participants first applied the brakes at an average distance of 328.7 ft from the intersection. Older participants (ages 45 to 84) applied the brakes farther upstream, especially at higher speeds, than their younger counterparts (ages 18 to 44). The probability of making a complete stop was found to vary significantly with average annual mileage (AAM) and expressed risk associated with performing rolling stops. Participants with higher AAM were found more likely to make complete stops. Intersection approaches were divided into five 98.4-ft segments, and total glance duration to eight regions of interest (ROIs) within each segment were analyzed. Drivers spent nearly the entire approach glancing to the forward ROI until they were 98.4 ft from the intersection. Between 0 and 98.4 ft, drivers spent an average of 5.1 s scanning the intersecting roadway; a total of 86.5 percent of all intersection scanning occurred in the last 98.4 ft of the approach. A novel difference was found among intersection crossings according to the type of stop performed. Drivers who came to a complete (0 mi/h) stop spent just 39.2 percent of their prestop time scanning the intersection, while rolling stoppers spent 74.5 percent. This suggests that complete stoppers focus on getting to the intersection and then stop, scan, and proceed, whereas rolling stoppers scan the intersection prior to arrival so that they can proceed at higher speeds while maintaining a perception of safety. |
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17. Key Words
Intersections, naturalistic driving, brake distance, complete and rolling stops, eyeglance duration, visual scanning |
18. Distribution Statement
No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161. |
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19. Security Classification Unclassified |
20. Security Classification Unclassified |
21. No. of Pages 49 |
22. Price
N/A |
Form DOT F 1700.7 (8-72) | Reproduction of completed page authorized |
SI* (Modern Metric) Conversion Factors
AAM | average annual mileage | |
CT | cross traffic | |
DUL | data use license | |
GEE | generalized estimating equation | |
GLM | generalized linear model | |
ICWS | intersection conflict warning system | |
ID | identification | |
IRB | Institutional Review Board | |
NDS | naturalistic driving study | |
PII | personally identifiable information | |
RID | Roadway Information Database | |
ROI | region of interest | |
SHRP2 | second Strategic Highway Research Program | |
SUV | sport utility vehicle | |
VTTI | Virginia Tech Transportation Institute | |
QIC | quasilikelihood under the independence model criterion |