Wing mirror

Dual-contour wing mirror. Large inboard convex surface is separated from small outboard aspheric surface.
Fender mirror on a Toyota Celsior
Wing mirror with inbuilt turn signal repeater
Side mirror with warning legend

A wing mirror, also known as the fender mirror, door mirror, or side view mirror, is a mirror found on the exterior of motor vehicles for the purposes of helping the driver see areas behind and to the sides of the vehicle, outside of the driver's peripheral vision (in the 'blind spot').

For mirrors on bicycles and motorcycles see "Rear-view mirror".

Although almost all modern cars mount their side mirrors on the doors, normally at the A-pillar, rather than the wings (fenders – portion of body above the wheel well), the "wing mirror" term is still frequently used.

The side mirror is equipped for manual or remote vertical and horizontal adjustment so as to provide adequate coverage to drivers of differing height and seated position. Remote adjustment may be mechanical by means of bowden cables, or may be electric by means of geared motors. The mirror glass may also be electrically heated and may include electrochromic dimming to reduce glare to the driver from the headlamps of following vehicles. Electrochromic auto-dimming technology[1] relies on a layer of electrochromic gel placed between two pieces of side mirror's glass and light sensors that measure brightness of the following vehicle's headlights and compare it to the brightness of ambient light. These inputs are used to dim the mirror. Increasingly, the side mirror incorporates the vehicle's turn signal repeaters. There is evidence to suggest mirror-mounted repeaters may be more effective than repeaters mounted in the previously predominant fender side location.[2]

Wing mirror on Korean-specification vehicle. Legend in Korean reads "Objects in mirror are closer than they appear".
Driver's control for Wing mirrors, with tiny curb-view button (saab 9-5).

Optional side mirror

In the 1940s many roads were unmade and had two lanes, one in each direction. Drivers had to be aware only of traffic on their side and directly behind them (rear view). Due to this, most passenger vehicles with an internal rear-view mirror until the late 1960s had the passenger-side mirror only as an optional addition, as it was considered a luxury.

Planar, convex, aspheric

In the U.S. and Canada, the U.S. National Highway Traffic Safety Administration's Federal Motor Vehicle Safety Standard 111 and the Canada Motor Vehicle Safety Standard 111 require the driver side mirror to provide "unity magnification", i.e., an undistorted 1:1 reflection achieved with a flat mirror. However, unity magnification limits the field of view that can be provided by a mirror of size compatible with the vehicle body. The ECE regulations in use throughout most of the world except North America permit the driver side mirror to have a planar, convex, or aspheric surface; an aspheric section is often combined with a larger convex section, and the two sections are separated by a visible line to alert the driver to the two sections' different perspective shifts.[3][4]

Because of the distance from the driver's eye to the passenger side mirror, a useful field of view can be achieved only with a convex or aspheric mirror. However, the convexity also minifies the objects shown. Since such objects seem farther away than they actually are, a driver might make a maneuver such as a lane change assuming an adjacent vehicle is a safe distance behind, when in fact it is quite a bit closer.[5] In the United States,[6] Canada,[7] India, Korea and Australia, non-planar mirrors are etched or printed with the warning legend objects in the mirror are closer than they appear. In Canada, this warning is often supplemented by a transparent decal on the passenger side window repeating the warning in French: les objets dans le retroviseur sont plus proche qu'ils ne le paraissent. In Korea, the warning appears in Korean. Warnings of this nature are not required in Europe.

Wing mirror retraction control (Saab 9-5)

Most side mirrors may be manually or electrically folded in, to protect them when the car is parked or being washed in an automated car wash. Passing cars can easily clip protruding wing mirrors; the folding capability helps protect them from harm.

Specifications

U.S. Federal Motor Vehicle Safety Standard 111 requires that convex side view mirrors must have a curvature radius of between 889 mm and 1651 mm.[6] Canada Motor Vehicle Safety Standard 111 stipulates a range of between 890 mm and 1800 mm.[7] Neither the U.S. nor the Canadian standard allows for aspheric mirrors.[4] The European ECE Regulation 46 used throughout most of the world permits planar, convex, and/or aspheric mirrors on either side of the vehicle.[4][8] American research suggests non-planar driver side mirrors may help reduce crashes.[3][9]

ECE Regulation 46 also requires that side mirrors be mounted such that they swing away when struck by a test cylinder meant to represent a pedestrian.[8]

See also

References

  1. ↑ "Replacement Outside Mirror".
  2. ↑ Flannagan, M.J.; Reed, M.P. (2005). "Geometric Visibility of Mirror-Mounted Turn Signals" (paper, PDF). Ref 2005-01-0449. Society of Automotive Engineers. Retrieved 14 August 2006.
  3. 1 2 Are Convex Driver Side Mirrors Helpful or Harmful?
  4. 1 2 3 Synthesis Study of Light Vehicle Non-Planar Mirror Research
  5. ↑ Why does the passenger side window on my car state 'objects in mirror are closer than they appear?'
  6. 1 2 Federal Motor Vehicle Safety Standard 111
  7. 1 2 Canada Motor Vehicle Safety Standard 111
  8. 1 2 ECE Regulation 46
  9. ↑ Response times using flat, convex, and multiradius rearview mirrors
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