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Improved Field of View
An approach to reducing motorcycle-car crashes is improving the fields of view of both the other vehicle drivers and riders. Research has examined modifications to car mirrors to improve field of view and also helmet design.
Modifications to car rear vision and side mirrors
Haworth and Smith (1999b) examined the involvement of a blind spot on the forward vehicle as a contributing factor to motorcycle crashes and examined possible changes to rear vision mirrors which could improve the performance of mirrors. From an analysis of Victorian and Australian crash data, they found that, as an upper bound estimate, the blind spot of another motor vehicle may have contributed to about 20.3% of motorcycle crashes. The estimated contribution to fatal crashes was lower than for other crashes (9.2% of Victorian crashes, 5.5% of Australian crashes).
Regulations in Australia, Japan and the United States require that the internal rear vision mirror be flat. Both Australia and the United States require that the driver side mirror be flat. The common rationale is that the most important mirrors should be flat to minimise distortions in distance and speed judgements. All of the four jurisdictions examined allowed passenger side mirrors to be flat or curved. Variations existed in terms of minimum radii of curvature, diameter and field of view.
Haworth and Smith (1999b) recommended that convex mirrors be allowed with a minimum radius of curvature of 1200mm and not as the main internal mirror (because of the danger of misperception of distance). The problems of misperception of distance can be reduced by using a compound mirror system, which consists of a flat (or relatively flat) section and a curved section. The flat part would be used for correct distance perception and the convex section used as a "presence" detector. The compound mirror system could be achieved by an aspheric mirror or by placing a small mirror with a small radius of curvature on the flat mirror. If an aspheric mirror is used, the proportion of the aspheric mirror over which the radius is changing should not exceed 40%. If a small mirror is attached to the flat mirror, the diameter of the small mirror should not exceed 40% of the height of the flat mirror.
Information sourced from A review of potential countermeasures for motorcycle and scooter safety across APEC (Full report and References [PDF, 304KB]). |
