Why your car mirrors reverse things horizontally instead of vertically?


Posted by: Oluwaseun Adeniji

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Have you ever wondered why mirror reverses objects horizontally and not vertically while driving? Some may take it for granted but inquisitive minds should not. Click here to see why!

One of the biggest concerns of any automaker is the safety of passengers using their products. This why they ensure that driving experience is safe enough by installing several safety features in their products. Some of these safety features include airbags, seatbelts, effective braking system, rear view mirrors and several others. These are features that make driving so enjoyable and memorable for every car owner.

Mirrors are without doubt the conventional safety features in vehicles. Rear-view mirror makes it easy to find out about the vehicle approaching from the back. The big question on this safety feature is; why does mirror reverse objects horizontally and not vertically? Let’s find out the answer to this here on Naijauto.

Why car mirrors reverse objects horizontally

These automobile’s rear view mirrors are plane mirrors belonging to special category. They make things to be seen larger and closer. In a plane mirror, things or objects are reversed left to right and definitely not top to the bottom. There is a reversal in the image of the mirror while the original image stays at a designated position. The axis and coordinate systems act vital role in the horizontal reversal of the images in the mirror.


Image appears horizontal in the vehicle's rear view mirror when on reverse mode

It is also possible to notice that the mirror installed in a car, horizontally reverses the image of the cars behind. This is why on emergency vehicles, the word ‘Ambulance’ is spelt out in reversed order for other road users to read it easily and correctly. In theory, an image is reversed in the plane mirror perpendicular to its axis, which in turn makes the object to be turned around in the mirror. This is why we say things are not reversed vertically in the mirror but horizontally.

Use of Mirrors and Signals

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When you decide to move your right hand in front of this car’s mirror, it reverses the direction of the image. A typical car’s mirror along its z-axis flips the image. This doesn’t deter or shift the position of the moving hand. This is why it could be a bit difficult to differentiate between two hands moving when there is a swapped image in the mirror. An image is never swapped top-down in the plane mirrors, making it an impossible driving task if vehicles behind are turned upside down.


The word 'Ambulance' is usually written backward for other drivers to read correctly via the reverse mirror

Final take 

The mirrors align with efficient symmetry. You might observe a swapped image in the mirror when you are perpendicular to it. This is why you can never see yourself upside down when looking at the mirror.

>>> Was this helpful? Get similar car tips and facts from Naijauto.com always!

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Oluwaseun Adeniji

Oluwaseun Adeniji

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Oluwaseun Adeniji is a passionate writer and a poet with special interest in writing about cars. He is a master degree holder in international conflict and management. He enjoys feeding the public with the latest auto gist and well researched car reviews. He is also a strong football lover. So, if Oluwaseun is not writing, expect him to be reading about sports.


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