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Monica Severson, Ergun Y. Uc, JonDavid Sparks, Matthew Rizzo; Effect of UFOV impairment on kinematics of curve driving. Journal of Vision 2007;7(9):148. doi: https://doi.org/10.1167/7.9.148.
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© ARVO (1962-2015); The Authors (2016-present)
Objective: To assess profiles of motor vehicle kinematics (control) in drivers with impaired Useful Field of View (UFOV) while approaching and driving on a curve.
Methods: Licensed, active drivers with impaired UFOV (n=5) due Alzheimer's disease (n=4) or stroke (n=5) and elderly controls (n=5) with no neurological disease with normal UFOV (1251±272 msec vs. 354±103, p[[lt]]0.0001, Wilcoxon Rank Sum) drove an instrumented vehicle on a 45 mph rural 2-lane highway. We assessed vehicle control measures (speed, steering, lateral and longitudinal acceleration, brake and accelerator pedal position) and lane violations on a straight baseline segment and during 10 second approach to a curve and while driving along the curve.
Results: There were no differences in vehicle control measures and lane violations between groups during the baseline segment. Compared to controls, drivers with high UFOV had a larger reduction in their speed while approaching the curve (7.1±2.2 mph vs. 1.6±1.3, p=0.009, Wilcoxon Rank Sum) and drove slower on the curve (44.6±1.6 mph vs. 46.3±1.2, p=0.047). Once in the curve, drivers with high UFOV showed a higher speed variability (1.5±0.5 mph vs. 0.9±0.4, p=0.047) and smaller mean steering wheel excursion (12.2±4.0 degrees vs. 17.1±2.5, p=0.028). The impaired UFOV group had a tendency to commit more lane violation errors (0.8±0.5 vs. 0.2±0.5, p=0.072) during approach to the curve, but not on the curve.
Conclusion: Drivers with impaired UFOV slowed down more than controls in preparation for entry into a curve, yet committed more safety errors during this phase. Despite possible compensatory strategies such as driving slower and with smaller mean steering wheel excursion on the curve (driving closer to the shoulder), the drivers with impaired UFOV showed reduced control of their vehicle speed. These findings suggest that curves represent an added challenge for vehicle control and driving safety for drivers with impaired UFOV.
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