We use mirrors to see behind us while driving. Almost all vehicles have one on either side, and those that have a rear window also have one in the centre of the windscreen. But, it wasn’t always like this. While they were first introduced in 1914, prior to the 1960s many vehicles didn’t have them, despite them being useful for manoeuvring and lane changing.
It’s not just as simple as not installing wing mirrors on a car, though, despite a multitude of concept cars being shown in the last few decades with video cameras replacing mirrors. For example, in the USA, legislation specifically mandates wing mirrors – something that Tesla is fighting to overturn, or at least soften.
What are the advantages of removing wing mirrors?
The cameras can be positioned to remove blind spots completely. Many people don’t know how to set wing mirrors. Or, when they get in a car that’s been driven by someone else they don’t want to spend the time adjusting them. With a camera system, the image will always be the perfect image covering all the blind spots.
The vehicle becomes narrower and more aerodynamic. The amount of drag the mirrors cause as a percentage of the overall drag depends on the vehicle’s shape, but on a car is between 2-7%, and that could translate into a lot of fuel saving. Without wing mirrors it’s easier for pedestrians to walk between parked cars, and it’s one less thing to damage while manoeuvring.
Wing mirrors are heavy as they have electric motors in. While they would need to be replaced by cameras and a screen, these will be lighter.
Camera-based systems used with other safety technology such as blind spot monitoring should almost eliminate accidents where a vehicle changes lanes and hits another vehicle. It will be especially useful for large vehicles such as lorries and buses where there are many more blind spots.
To look at the side mirror a driver has to take their eyes off the road. To change to a more centrally located screen means drivers are looking in a direction that is angled more forwards meaning they can see more of the road ahead in their peripheral vision.
What are the disadvantages of removing wing mirrors?
Adding more electrical technology to a vehicle means there’s more to go wrong. Standard mirrors are very reliable in all types of weather and only become useless if they are smashed, but if a screen fails then the driver would not be able to see at all.
Camera technology is not good enough to provide the kind of resolution that mirrors can provide in the widely variable light levels that we drive in (blinding sunlight down to almost pitch black). The cameras also have a very small amount of lag (delay) from recording the image through to rendering it on the screen.
The screens will have to be placed inside the vehicle, but where? Our vehicles’ dashboards are already cluttered with media options, air conditioning and other functions. Perhaps a really wide screen where the rear-view mirror is would be the best option, and this view is (kind of) already available by using extremely convex rear-view mirrors.
We are used to seeing and using wing mirrors. It’s possible that people won’t initially like the look of a vehicle without wing mirrors, or won’t like using a screen-based system.
When will the change occur?
Some vehicles already come with a video camera for the rear-view mirror – the odd supercar that has seriously compromised rear vision, for example. So, the technology already exists.
Vehicles that are built for specific markets that don’t have this legislation (e.g. Germany and Austria) can already have their wing mirrors deleted, but most manufacturers make global vehicles so that the cost of development is amortised over a number of markets. There’s no reason, though, why a camera-based system can’t be used in conjunction with a conventional mirror, except that it’s an extra cost which would have to be borne by the consumer. As there’s no pressing safety need to remove wing mirrors, the public is apathetic and it’s just companies like Tesla which are looking to eke out fuel consumption gains that are pushing the cause.
The change may be more difficult to implement on motorbikes because of the exposed electronics involved in having a screen, plus the potentials for glare on the screen. However, there are HUD (head-up display) systems available that project information onto the inside of the visor and, with a rearward-facing camera, this could provide more information about what’s over the shoulder of a biker, adding extra safety for when the rider makes those lifesaver glances before changing lanes or turning.
For lorries, a system which backs up the mirrors would be extremely useful, at least for covering blind spots and looking behind long trailers.