AUTO History      

 

    On most early motor vehicles, the driving seat was positioned centrally. Some car manufacturers later chose to place it on the side of the car closest to the kerb to help the driver avoid scraping walls, hedges, gutters and other obstacles. Other car manufacturers placed the driving seat on the side closest to the centre of the road to give the driver the longest possible line of sight in traffic. This is the pattern that eventually prevailed. Today experimental versions of drive by wire and brake by wire vehicles are being developed which allow the driver to slide the steering wheel/brake controls from left to right with the gauges in the centre dashboard. They are expected to become popular in countries such as Thailand that have land borders with opposite-drive countries. The newest Unimog models can be changed from left-hand drive to right-hand drive in the field to permit operators to work on the more convenient side of the truck.

       Rear-View Mirror

      rear-view mirror is a mirror in automobiles and other vehicles, designed to allow the driver to see rearward through the vehicle's backlight (rear windscreen).

In cars, the rear-view mirror is usually affixed to the top of the windscreen on a double- swivel mount allowing it to be adjusted to suit the height and viewing angle of any driver and to swing harmlessly out of the way if impacted by a vehicle occupant in a collision . In the past, some cars had the rear-view mirror mounted on top of the dashboard .

The rear-view mirror is augmented by one or more side-view mirrors , which serve as the only rear-vision mirrors on motorcycles and bicycles

Rear-view mirror showing cars parked behind the vehicle containing the mirror

 

     


 

 

A wing mirror (also fender mirrordoor mirror , or side 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').

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. However, wing mirrors continue to be relatively common in the Japanese domestic marketcitation needed ] The mirrors on bicycles and motorcycles are usually mounted to the handlebars, and there are usually two of them. citation needed ]

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. 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. [ 1 ]

 

Planar, convex, aspheric

US the US National Highway Traffic Safety Administration 's Federal Motor Vehicle Safety Standard 111 and the analogous Canada Motor Vehicle Safety Standard 111 require the driver side mirror to provide "unit magnification", ie, an undistorted 1:1 reflection achieved with a flat mirror. However, unit 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, and/or asphericsurface; 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. [ 2 ] [ 3 ]

Because of the distance from the driver's eye to the passenger side mirror, a useful field of view can only be achieved with a convex or aspheric mirror. However, the convexity also minifiesthe objects shown. Since minified 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. [ 4 ] In the United States[ 5 ] Canada[ 6 ] India and Australia citation needed ] , passenger-side mirrors are etched or printed with the warning legend objects in 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 se paraissent . Warnings of this nature are not required in Europe, where the proliferation of languages would make it difficult to implement a universally-comprehensible warning.

Side mirrors are easily damaged
Wing mirror retraction control ( Saab 9-5 )

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

edit ]Specifications

US Federal Motor Vehicle Safety Standard 111 requires that convex side view mirrors must have a curvature radius of between 889 mm and 1651 mm. [ 5 ] Canada Motor Vehicle Safety Standard 111 stipulates a range of between 890 mm and 1800 mm. [ 6 ] Neither the US nor the Canadian standard allows for aspheric mirrors. [ 3 ] The European ECE Regulation 46 used throughout most of the world permits planar, convex, and/or aspheric mirrors on either side of the vehicle. [ 3 ] [ 7 ] American research suggests non-planar driver side mirrors may help reduce crashes. [ 2 ] [ 8 ]

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. [ 7

 



 
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