Why Are Vehicle Mirrors Slightly Curved?

Slightly curved vehicle mirrors make the objects in mirror seem closer than they appear. But what's their function? Let's find out!

Why Are Vehicle Mirrors Slightly Curved?

Your vehicle has a few strategically placed mirrors that make the driving experience a lot easier and safer. You might have noticed that some mirrors are flat, while others are slightly curved. Why is that?

In general, the mirror on the passenger’s side is a convex one which means that it’s slightly curved. Thanks to this shape, the mirror is able to diminish the objects that it reflects – this allows the driver to have a much wider field view.

What are the disadvantages of curved mirrors and when were they first introduced? Let’s dive deeper into the topic.

Why Are Vehicle Mirrors Slightly Curved?

Curved mirrors are also called ‘convex mirrors’. They have a reflective surface that bulges outward, toward the source of light. Such a shape makes it possible for the mirror to highly diminish the objects in it.

In vehicles, convex mirrors are used to provide a much wider field of view. Thanks to this feature, drivers have a better understanding of what’s happening around the vehicle.

Slightly curved mirrors, of course, have their own cons. Objects in them seem farther than they actually are and the shape of the objects can become a bit distorted.

It is important for a driver to know about these peculiarities to be able to properly use the mirror and drive safely.

Fact: Convex mirrors are also used in shops, along the roadside, on construction sites, at ATMs, and so on.

Are the Passenger-Side and Driver-Side Mirrors Different?

You might have noticed that passenger- and driver-side mirrors are different. The former are the ones that are slightly curved forward.

Such a convex mirror allows the driver to have a wider field of view and the curve also helps minimize the blind spots. However, there is one major downside of such a shape – the objects that you see in this mirror will appear farther apart and will be a bit distorted.

Passenger-side mirror Driver-side mirror
Shape Slightly curved Flat
The field of view Wider Much narrower
Distortion Objects seem farther and there is a distortion in shape You’ll see an exact reflection of what’s happening behind you

As you can see, these two mirrors are quite different. However, the drivers who know how to use both of them at a glance will have a practically complete understanding of what’s happening around the vehicle (without having to constantly swivel their heads).

By the way, some automakers like to add a small convex mirror to the flat driver-side mirror to give a slightly wider field of view.

When it comes to larger vehicles, such as school buses, for example, they might have convex mirrors mounted on both sides of the bus (right under the flat mirrors).

Are Interior Mirrors Slightly Curved?

In general, only the passenger-side exterior mirror is slightly curved. The majority of interior mirrors are completely flat.

Such a shape of the rear-view mirror allows the driver to judge the position and the speed of other vehicles more accurately. The objects that they show are completely undistorted and the size of the objects and the distance to them are accurately reflected.

Why Don’t Flat Mirrors Work on the Passenger’s Side?

A regular flat mirror wouldn’t work as well as a slightly curved one on the passenger’s side as the driver would only be able to see a small area alongside the car.

No matter how you adjust the flat mirror on the passenger’s side, you won’t be able to get a clear view of what’s going on behind the vehicle.

Of course, it is extremely important to properly adjust a slightly curved mirror for it to work its magic. Remember that when sitting straight, you shouldn’t be able to see any part of your car in the side mirrors.

The History of Vehicle Mirrors

Way back in 1911, racer Ray Harroun decided that rear-view mirrors could be helpful in high-speed driving. With such an extra feature, you wouldn’t have to ask your friend to check, if it’s safe to change the lanes – you’ll have full control of your driving.

However, a rear-view mirror was patented only ten years later, in 1921. Elmer Berger called the mirror the ‘cop-spotter’ as he used it mainly to look out for police officers.

Mirrors started to become standard equipment only in the 1960s after multilane highways were built and the National Traffic and Motor Vehicle Safety Act was enacted.

When it comes to passenger-side mirrors, those have become standard equipment on vehicles a few decades ago. The chances are high that very soon there will, once again, be no need for these specific mirrors due to the development of sensors and cameras.

The Evolution of the Curved Mirror

The mirrors on the driver’s side have always been flat in the United States, but it doesn’t have to always be like that.

Dr. R. Andrew Hicks, a mathematics professor at Drexel University, created a subtly curved driver’s mirror that has a field view of about 45 degrees (traditional flat mirrors have a field view of 15-17 degrees).

The best part about this innovative mirror is that, unlike regular passenger-side mirrors, this one provides a wider field view without squashing the perceived shape of objects. In fact, any visual distortions are barely detectable in Hick’s new mirror.

However, this invention can’t be installed on the cars sold in the United States any time soon as there are regulations that dictate that the driver’s side can have only a flat mirror.

In some other countries, it is allowed to install slightly curved mirrors on the driver’s side in new cars. Moreover, Hick’s creation can be added to a car after the initial purchase (installing such a mirror is a lot cheaper than investing in a vehicle with a camera).

The flat-convex duo has been a standard in the United States for years. Nowadays, the US Department of Transportation is looking into the safety benefits of two slightly curved mirrors (one for the driver’s and one for the passenger’s side), so we might start using more convex mirrors in the future.