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Table of Content

This Document is disseminated under the Sponsorship of the Department of Transportation, National Highway Traffic Safety Administration, in the interest of information exchange. The United States Government assumes no liability for its contents or the use thereof. This report does not constitute a standard, specification, or regulation.

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Technical Report Documentation Page

1. Report No.

2. Government Accession No.

3. Recipient's Catalog No.
4. Title and Subtitle

INTERSECTION NEGOTIATION PROBLEMS OF OLDER DRIVERS, Volume II: Background Synthesis on Age and Intersection Driving Difficulties

5. Report Date

September 1998

6. Performing Organization Code

1446

7. Author(s)

Loren Staplin, Kathy H. Lococo, A. James McKnight,
A. Scott McKnight, and Germaine L. Odenheimer

8. Performing Organization Report No.

1446/FR

9. Performing Organization Name and Address

The Scientex Corporation
Transportation Safety Division
P.O. Box 1367, 1722 Sumneytown Pike
Kulpsville, PA 19443

10. Work Unit No. (TRAIS)
11. Contract or Grant No.

DTNH22-93-C-05237

12. Sponsoring Agency Name and Address

Office of Research and Traffic Records
National Highway Traffic Safety Administration
400 Seventh Street, S.W., Room 6240
Washington, DC 20590

13. Type of Report and Period Covered

Background Synthesis

Oct. 1993 - Sept. 1997

14. Sponsoring Agency Code

15. Supplementary Notes

16. Abstract

This project included a background literature synthesis and observational field study. The research goals were to document driving problems and errors at intersections, for older drivers using their own cars to travel familiar and unfamiliar routes, and to measure how well they could be predicted by prior tests given in an office setting. Volume I presents the field study methodology and results; Volume II presents the background synthesis.



Field observations of intersection negotiation were conducted using 82 subjects, age 61 and older, referred to the California Department of Motor Vehicles for special testing. The subjects first completed a functional test battery measuring vision, attention capabilities, and head/neck flexibility. They then underwent on-road testing administered by DMV examiners. Subjects were administered the test on both an unfamiliar and familiar route, unless the testing was prematurely terminated for safety reasons. During the on-road tests, a miniature, multiple-camera apparatus in the driver's own vehicle recorded visual search behaviors, brake and accelerator use, and traffic events in the forward scene. Analysis of the videotaped data revealed a high incidence of visual search errors. Many common behaviors were included (such as failure to look to the sides when traveling through an intersection on a green light) that were technical errors, but which rarely require an emergency response. The highest error rate for an actual maneuver, as captured by the cameras, was making a lane change with an unsafe gap. This problem was exaggerated on the low familiarity test route, where drivers had no expectation of where the next turn would occur. Analysis of errors recorded by the DMV examiners followed the same general pattern as the video-based error taxonomy, where scanning errors predominated across both familiar and unfamiliar test routes, and maneuver errors occurred less frequently. Those driving errors observed most often by the examiners included failure to stop completely at a stop sign, stopping over a stop bar, improper turning path, and stopping for no reason. Regression analyses examined the relationships between functional test results and weighted examiners' error scores. Speed of response on visual discrimination tasks was the best predictor, but no single measure accounted for more than 18% of variance on the criterion.

17. Key Words

Driver, Safety, Mobility, Age, Intersection, Familiarity, Functional Impairment, Functional Testing, Road Test, Licensing, Screening, Vision, Attention, Maneuver Errors

18. Distribution Statement

No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.

19. Security Classif. (of this report)

Unclassified

20. Security Classif. (of this page)

Unclassified

21. No. of Pages

138

22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized