This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Rearward Vision, Driver Confidence, and Discomfort Glare Using an Electrochromic Rearview Mirror
Annotation ability available
Sector:
Language:
English
Abstract
Electrochromic rearview mirrors can provide continuous levels of reflectivity and unobtrusive, automatic control. The availability of this technology has increased the importance of understanding how to select the best level of reflectivity for a given set of lighting conditions. For night driving with glare from following headlights, the best reflectivity level will always depend on a tradeoff among several variables. This study was designed to help clarify what variables are important and how they should be quantified.
Twenty subjects, 10 younger and 10 older, performed a number of visual tasks while viewing stimuli through an electrochromic rearview mirror. Subjects were seated in an automobile mockup in a laboratory, and the reflectivity level of the mirror was changed before each of a series of discrete trials. On each trial, subjects saw reflected in the mirror a visual-acuity stimulus and a glare source of varying intensity. They performed three tasks: (1) judgment of the location of a gap in the acuity stimulus, (2) rating of their subjective confidence in the gap judgment, and (3) rating of the discomfort they experienced from the glare source.
Results showed that: (1) visual performance decreased with decreasing reflectivity approximately as a linear function of log reflectivity, (2) subjects' confidence consistently underestimated their actual performance but otherwise accurately reflected the effect of reflectivity on performance, and (3) the effect of reflectivity on discomfort glare is not fully predicted by its effect on illumination at the subject's eye point.
Implications of these findings for mirror design include: (1) the continuous reflectivity control provided by electrochromic mirrors should be of value in achieving optimal tradeoffs in the presence of glare, and (2) at least for discrimination tasks, even though changes in reflectivity are automatic and subtle, subjects recognize the resulting changes in seeing ability.
Recommended Content
| Technical Paper | An Advanced Optic Rear Vision Device for Motor Vehicles |
| Technical Paper | Quantifying the Benefits of Variable Reflectance Rearview Mirrors |
Authors
Citation
Flannagan, M., Sivak, M., and Gellatly, A., "Rearward Vision, Driver Confidence, and Discomfort Glare Using an Electrochromic Rearview Mirror," SAE Technical Paper 910822, 1991, https://doi.org/10.4271/910822.Also In
Vehicle Lighting Design for Optimal Visibility and Performance
Number: SP-0857; Published: 1991-02-01
Number: SP-0857; Published: 1991-02-01
References
- Bhise, V. D. Swigart, T. F. Farber, E. I. 1975 Development of a headlamp dimming request prediction model Human Factors in Our Expanding Technology. Proceedings of the Human Factors Society 19th Annual Meeting Santa Monica: Human Factors Society
- de Boer, J. B. 1967 Visual perception in road traffic and the field of vision of the motorist de Boer J. B. Public lighting 11 96 Eindhoven, The Netherlands Philips Technical Library
- Flannagan, M. 1988 Human performance aspects of rearview mirrors An applied-literature review (Report No. UMTRI-88-20) Ann Arbor, MI The University of Michigan Transportation Research Institute
- Flannagan, M. Sivak, M. 1990 Nighttime effectiveness of rearview mirrors Driver attitudes and behaviors (SAE Technical Paper Series # 900567 ) Warrendale, Pennsylvania Society of Automotive Engineers
- Helder, D. J. 1987 Design parameters for an automotive interior mirror (SAE Technical Paper Series # 870635 ) Warrendale, Pennsylvania Society of Automotive Engineers
- Lynam, N. R. 1987 Electrochromic automotive day/night mirrors (SAE Technical Paper Series # 870636 ) Warrendale, Pennsylvania Society of Automotive Engineers
- Olson, P. L. Jorgeson, C. M. Mortimer, R. G. 1974 Effects of rearview mirror reflectivity on drivers' comfort and performance (Report No. UM-HSRI-HF-74-22) Ann Arbor, MI The University of Michigan Highway Safety Research Institute
- Olson, P. L. Sivak, M. 1984 Glare from automobile rear-vision mirrors Human Factors 26 269 282
- Schmidt-Clausen, H.-J. Bindels, J. Th. H. 1974 Assessment of discomfort glare in motor vehicle lighting Lighting Research and Technology 6 79 88
- Sivak, M. Flannagan, M Ensing, M Simmons, C. J. 1989 Discomfort glare is task dependent (Report No. UMTRI-89-27) Ann Arbor, MI The University of Michigan Transportation Research Institute