title: Characteristics of turn signal use at intersections in baseline naturalistic driving.
abstract: The purpose of this study was to determine whether a driver's use of turn signals is sufficiently reliable to forecast a vehicle's future path around an intersection, when detailed information about the intersection is unavailable. Naturalistic observations of turn signal use among 108 drivers on surface streets were extracted from the baseline portion of a field operational test of a safety system. Left and right turns that resulted in heading changes of between 70 and 110° and turn radii between 18 and 90 m were selected from the dataset. The odds that a driver would signal a turn were modeled as a function of road type, turn direction, presence of a forward vehicle, whether the vehicle stopped before the turn, and driver age and gender. Overall, 25 percent of left turns and 29 percent of right turns were not signaled. Road type, turn direction, and presence of a forward vehicle were found to influence the odds that a turn is signaled, while gender and age of the driver did not. The results suggest that situational factors like road type and turn direction are more powerful predictors of whether a turn will be signaled than either age or gender. Signaling on major and minor surface roads was about 5 times more likely than on local roads and 1.5 times more likely when a forward vehicle was present, suggesting a possible effect of traffic volume. It was concluded that turn signal activation alone may be insufficiently reliable to forecast a driver's path.
authors.affiliation: University of Michigan Transportation Research Institute, 2901 Baxter Rd., Ann Arbor, MI 48109-2150, USA. Electronic address: jsully@umich.edu.
authors.forename: John M
authors.initials: JM
authors.lastname: Sullivan
authors.affiliation: University of Michigan Transportation Research Institute, 2901 Baxter Rd., Ann Arbor, MI 48109-2150, USA. Electronic address: shanbao@umich.edu.
authors.forename: Shan
authors.initials: S
authors.lastname: Bao
authors.affiliation: Nissan Technical Center North America, 39001 Sunrise Drive, Farmington Hills, MI 48331-3287, USA. Electronic address: goudyr1@nrd.nissan-usa.com.
authors.forename: Roy
authors.initials: R
authors.lastname: Goudy
authors.affiliation: Nissan Technical Center North America, 39001 Sunrise Drive, Farmington Hills, MI 48331-3287, USA. Electronic address: KonetH@nrd.nissan-usa.com.
authors.forename: Heather
authors.initials: H
authors.lastname: Konet
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000328:Adult; D000367:Age Factors; D000368:Aged; D001334:Automobile Driving / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009633:Nonverbal Communication; D012449:Safety / Q000706:statistics & numerical data*; D012737:Sex Factors; D055815:Young Adult
keywords: Forward vehicle; Surface streets; Turn direction; Turn signal use