Citation

Henderson S, Gagnon S, Collin C, Tabone R, Stinchcombe A. Proc. Int. Driv. Symp. Hum. Factors Driv. Assess. Train. Veh. Des. 2009; 5: 334-341.

Copyright

(Copyright © 2009, University of Iowa Public Policy Center)

DOI

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PMID

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Abstract

The method of descending limits assessed motion contrast thresholds of 11 young participants (17–28), and 21 older drivers (63–86) for 0.4 cycle/degree drifting Gabor stimuli at 15 degrees eccentricity. Peripheral motion contrast thresholds (PMCT) of younger participants (M = –45.5 dB, SD = 1.66 dB) and older participants (M = –43.3 dB, SD = 3.79 dB) differed (t(29) = 2.295, p < .05 (all p-values one-tailed)). Older drivers performed UFOV® tests and a high-fidelity driving simulation. Between independent variables, significant correlations were PMCT with UFOV2 (r = .74, p < .001), PMCT with UFOV3 (r = .50, p < .01), PMCT with age (r =.73, p < .001), UFOV2 with age (r = .48, p < .05), and UFOV3 with age (r = .44, p < .05). Between vision and simulator measures, PMCT and UFOV2 significantly predicted rater’s simulator score (r = .66, p < .001; r = .58, p < .01 respectively), and simulator crashes ( r = .63, p < .001; r = .72, p < .001 respectively). Thus, PMCT and UFOV2 strongly predicted simulator performance. Partial correlations showed that: substantial association between PMCT and UFOV2 was not age–related; PMCT and UFOV2 tapped a common visual function; and PMCT assessed a component not captured by UFOV2. The descending limits procedure is as reliable and faster than forced- choice. A practicable PMCT test that informs at-risk drivers about visual deficits may help them compensate effectively by learning voluntary scanning techniques and by otherwise modifying their driving techniques.