question: How does the other "side" of the rearview mirror prevent glare?
comment: The mirror has an odd shape called a prism, so that when you tilt it, the reflection off the surface of the glass is more noticeable than the reflection off the mirror surface under the glass. A mirror has a shiny coating on the back of the glass to make the bright reflection. Any flat glass will show a weak reflection if you watch it at an angle. The car mirror is made so the bright reflection is not lined up with the weak reflection, usually showing the dark inside of the car, letting the weaker surface reflection show through.
passages: On manual tilt versions, a tab is used to adjust the mirror between "day" and "night" positions. In the day view position, the front surface is tilted and the reflective back side gives a strong reflection. When the mirror is moved to the night view position, its reflecting rear surface is tilted out of line with the driver's view. This view is actually a reflection off the low-reflection front surface; only a much-reduced amount of light is reflected into the driver's eyes.
   Current systems usually use photosensors mounted in the rear-view mirror to detect light and dim the mirror by means of electrochromism. This electrochromic feature has also been incorporated into side-view mirrors allowing them to dim and reduce glare as well.
  
  Section::::Trucks and buses.
   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 "unit magnification", i.e., 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, 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.
   The rear-view mirror is augmented by one or more side-view mirrors, which serve as the only rear-vision mirrors on trucks, motorcycles and bicycles.
  
  Section::::History.
   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. Canada Motor Vehicle Safety Standard 111 stipulates a range of between 890 mm and 1800 mm. Neither the U.S. nor the Canadian standard allows for aspheric mirrors. The European ECE Regulation 46 used throughout most of the world permits planar, convex, and/or aspheric mirrors on either side of the vehicle. American research suggests non-planar driver side mirrors may help reduce crashes.
  
  Section::::See also.
  
  BULLET::::- Automatic parking
  
  BULLET::::- Backup collision
  
  BULLET::::- Backup camera
  
  BULLET::::- Blind spot monitor
   A prismatic rear-view mirror—sometimes called a "day/night mirror"—can be tilted to reduce the brightness and glare of lights, mostly for high-beam headlights of vehicles behind which would otherwise be reflected directly into the driver's eyes at night. This type of mirror is made of a piece of glass that is wedge-shaped in cross section—its front and rear surfaces are not parallel.
   Section::::Automotive.
  
  Section::::Automotive.:Automatic interior mirror.
  
  Gentex first introduced a rear-view mirror that automatically adjusted to glare conditions in 1982.
  
  Section::::Automotive.:Auto-dimming mirrors.
  
  Section::::Automotive.:Auto-dimming mirrors.:Interior.
  
  Gentex introduced an automatic dimming mirror based on electrochromism in 1987. The reduction of glare eliminates the temporary blind spot caused by the Troxler effect after the glare source leaves the field of view.
  
  These mirrors have forward- and rearward-facing sensors to measure the ambient light level and glare of approaching vehicles, respectively. An electrochromic gel is placed between two pieces of glass, which allows the mirror to dim in proportion to the glare level.
  
  Section::::Automotive.:Auto-dimming mirrors.:Exterior.
   Section::::Optional side mirror.
  
  In the 1940s many roads were unpaved 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.
  
  Section::::Planar, convex, aspheric.
   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. In the United States, Canada, India, Korea and Australia, non-planar mirrors are etched or printed with the warning legend . In Canada, this warning is often supplemented by a transparent decal on the passenger side window repeating the warning in French: . In Korea, the warning appears in Korean. Warnings of this nature are not required in Europe.
   Section::::Planar, convex, aspheric.:Other requirements.
  
  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. 
  
  ECE Regulation 46 requires that side mirrors be mounted such that they swing away when struck by a test cylinder meant to represent a pedestrian.
   Today’s windshields are a safety device just like seatbelts and airbags. The urethane sealant is protected from UV in sunlight by a band of dark dots around the edge of the windshield. The darkened edge transitions to the clear windshield with smaller dots to minimize thermal stress in manufacturing. The same band of darkened dots is often expanded around the rearview mirror to act as a sunshade.
  
  Section::::Other aspects.
   In binoculars with Schmidt–Pechan roof prisms, mirror coatings are added to some surfaces of the roof prism because the light is incident at one of the prism's glass-air boundaries at an angle less than the critical angle so total internal reflection does not occur. Without a mirror coating most of that light would be lost. Schmidt–Pechan roof prism aluminum mirror coating (reflectivity of 87% to 93%) or silver mirror coating (reflectivity of 95% to 98%) is used.
   BULLET::::- Digital compass in rearview mirror
  
  BULLET::::- XM Satellite Radio "(optional on 2006 RTLs)"
  
  BULLET::::- Power moonroof "(optional on 2006 RTLs)"
  
  BULLET::::- 2009 model year updates added:
  
  BULLET::::- machine finished aluminum alloy rims, similar in design to the Sport trim's rims
  
  BULLET::::- Fog lights
  
  BULLET::::- 115 V/100 W alternating current (AC) inverter
  
  BULLET::::- 2013 model year updates removed the digital compass from the rearview mirror in lieu of the backup camera display
   Elmer Berger is usually credited with inventing the rear-view mirror, though in fact he was the first to patent it (1921) and develop it for incorporation into production streetgoing automobiles by his Berger and Company.
  
  Section::::Augmentations and alternatives.
   BULLET::::- A prismatic star diagonal for an astronomical telescope may consist of a single Porro prism (configured for a single reflection, giving a mirror-reversed image) or an Amici roof prism (which gives a non-reversed image).
  
  BULLET::::- Roof prisms use TIR at two faces meeting at a sharp 90° angle. This category includes the Koenig, Abbe–Koenig, Schmidt–Pechan, and Amici types (already mentioned), and the roof pentaprism used in SLR cameras; the last of these requires a reflective coating on one face.
  
  BULLET::::- A prismatic corner reflector uses three total internal reflections to reverse the direction of incoming light.
   There are three types of rearview cameras. 
  
  Surface Mounted
  
  Flush Mounted
  
  License Mounted
  
  Surface Mounted Cameras
  
  These cameras are mounted on a flat surface of the vehicle by focusing them high up. By doing so they provide a perfect view and an excellent depth perception. These features make this type of camera to be more efficient and that’s why they are chosen for larger vehicles so they would produce a better picture with a wider angle.
  
  Flush Mounted Cameras
   Washington State’s Department of Labor and Industries studied hardhat mounted mirrors’ effectiveness as a run-over and back-over safety device. The study, done in 2000, is titled “Optical Properties of Plane and Convex Mirrors: Can Mirrors Be Used to Enhance Construction Flaggers’ Safety?” The conclusion states: “Given that image perception is a problem with small-radius-of-curvature convex mirrors and that it is difficult for a flagger to view the flagpole mirror and keep an eye on traffic in front of them, helmet mirrors have been found to be the best option for flaggers.”
  
  Section::::History.
   Most modern cars have two sun visors, one for the driver's side and a second for the passenger's side, with the rear-view mirror often mounted in between the two sun visors. Each visor can be lowered to help block light from the sun entering through the windshield. Some are designed so they can be released from one bracket and be turned towards the side window, covering a small part of the window at the top to block sunlight shining onto the side of the face. Some current visors can also be extended along the side window to block sunlight all of the way to the "B" pillar to block the light for the driver or passenger.
   A new headlamp design with projectors is offered for Xenon lamps. Headlamps washers now pop up from beneath body color moulding in the bumpers. A new alloy wheel complements the existing range of 16 inch (steel and alloy) and 17 inch (alloy) designs. V8 models are given a discreet V8 badge at the leading edge of both front doors and a new side moulding across the doors.
  
  Section::::Fourth generation R52 series (2013–present).
   BULLET::::- Mirrors, Dual-Head: An expanded field of vision to the rear and both sides of the truck is available by ordering these dual-head mirrors. Each of the western-type mirror frames holds two 6x6-inch mirrors-a flat one which provides a standard rear view with objects in proper perspective and a convex one which offers a panoramic view to eliminate blind spots. Especially helpful for trailer towing.
   Until 1983, Japanese Ministry of Transport did not allow to register cars without mirrors on front fenders, so the mirrors were mounted far forward atop the front fenders. More recent Japanese-specification vehicles have side mirrors similar to those in other countries.
   BULLET::::- T-bar glass panels changed from smoked (clear) to mirrored (opaque)
  
  BULLET::::- Color-code door handle and side mirrors for all models
  
  BULLET::::- Incandescent third brake lamp replaced by LED strip integrated into the rear spoiler
  
  BULLET::::- More aerodynamic wing mirrors introduced, with optional power retract mechanism
  
  BULLET::::- North American supercharged models equipped with rear anti-roll bar
   On the tailgate, the area between the taillamps became partially recessed (as on 1980s versions), with the option of chrome trim. The taillamp assembly also houses the blind spot monitor; these systems were not typically included on pickup trucks because the system could not be packaged inside steel bumpers typically found on pickup trucks.
  
  Section::::Trim.
   Rear-view mirror
  
  A rear-view mirror (or rearview mirror) is a Convex mirror in automobiles and other vehicles, designed to allow the driver to see rearward through the vehicle's rear window (rear windshield).
  
  In cars, the rear-view mirror is usually affixed to the top of the windshield 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.
   The light striking the rear, inside surface of the prisms or beads, does so at an angle greater than the critical angle thus it undergoes total internal reflection. Due to the orientation of the other inside surfaces, any light internally reflecting is directed back out the front of the reflector in the direction it came from. This alerts the person close to the light source, e.g. the driver of the vehicle, to the presence of the cyclist.
  
  Section::::See also.
  
  BULLET::::- High-visibility clothing
  
  BULLET::::- Retroreflector
  
  Section::::External links.
  
  BULLET::::- Driving simulator that highlights the benefits of safety reflectors (Finnish Road Safety Council)
  
raw_presuppositions: The other side of the rearview mirror prevents glare.
raw_corrections: When you tilt it, the reflection off the shiny coating shows the dark inside of the car and the reflection of the glass is more noticeable.