Aspherical Convex Mirrors Improve Operator Judgement in Heavy Commercial Vehicles 952654
Spherical convex auxiliary mirrors are commonly used on commercial vehicles to expand the field of view (FOV) beyond the limited FOV (approximately 10 degrees lefl and 4 degrees right) available in flat mirrors commonly referred to as “West Coast Mirrors”.
Unfortunately the tradeoff with the short radius spherical convex mirrors used to obtain the desired FOV is a dramatic reduction (95% or greater) in apparent image size. This much reduced image size provides the vehicle operator with information sufficient to detect the presence or absence of adjacent vehicles, but is of limited use in making the relative speed and relative distance judgements required for lane changes.
Considerable efforts are being expended to develop relatively high cost electronics based object detection and warning systems. However, vehicle operators at a relatively b w cost, can obtain the larger image sizes and much of the information needed for good driving judgements through the use of multi radiused aspherical mirrors. Such mirrors can better manage the required design tradeoffs between:
Large image size with good distance judgement, and
An extended wide angle FOV that substantially reduces the side blind spots.