Conference Proceeding

Neuropsychological Predictors of Safety in Urban Left-Turn Scenarios

  • Jeffrey D Dawson (University of Iowa, Iowa City, IA)
  • Lixi Yu (University of Iowa, Iowa City, IA)
  • Kuan-Hua Chen (University of Iowa, Iowa City, IA)
  • Michelle Rusch (University of Iowa, Iowa City, IA)
  • Amy M Johnson (University of Iowa, Iowa City, IA)
  • Nazan S Aksan (University of Iowa, Iowa City, IA)
  • Takashi Sunda (Nissan Motor Co., Ltd., Japan)
  • Machiko Hiramatsu (Nissan Motor Co., Ltd., Japan)


Left turns at urban intersections can be dangerous, especially when views are obstructed or pedestrians are present. Impairments in driver vision, motor, and cognition functions may further increase left-turn risk. We examined this problem in a simulated environment that included left-turn scenarios to study the driving behaviors of 28 drivers, ages 37 to 88 years, six of whom had “Useful Field of View” (UFOV) impairments. Subjects also completed a battery of neuropsychological tests. The simulated drive included an urban section with six left turns in three types of scenarios: 1) a semi truck blocking the view of oncoming traffic, 2) a lead vehicle obstruction, and 3) a pedestrian crossing ahead of the turning driver. Results showed a mean (SD) of 1.46 (1.60) collisions per driver (range 0 to 7), 83% of which occurred at intersections with semi trucks. Far visual acuity, contrast sensitivity, UFOV, Mini Mental State Examination, TrailMaking Test Part B, the Wisconsin Card Sort task, and age were all associated with the total number of collisions (Pearson correlation magnitudes between 0.37 to 0.77; p-values<0.05). Spearman correlations were less significant. Findings indicate that visual obstruction by on oncoming semi-truck is a particularly dangerous left-turn situation.

How to Cite:

Dawson, J. & Yu, L. & Chen, K. & Rusch, M. & Johnson, A. & Aksan, N. & Sunda, T. & Hiramatsu, M., (2013) “Neuropsychological Predictors of Safety in Urban Left-Turn Scenarios”, Driving Assessment Conference 7(2013), 226-232. doi:

Rights: Copyright © 2013 the author(s)

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Published on
18 Jun 2013
Peer Reviewed