The heads-up display (HUD) is a safety system designed to keep you from taking your eyes off the road by projecting data on your windshield. This way, you don't have to look down to check information about your trip or car or look at the infotainment display.

The technology behind the HUD isn't a recent innovation. It was first used on fighter jets 70 years ago for faster and safer flights during the night. So, unless you are a jet pilot, there's a fair chance you haven't encountered this technology outside video games, as mainstream cars usually don't come with HUD.

At least, not yet.

How Does a Car HUD Work?

A HUD uses a simple physics phenomenon to show data on your windshield: reflection. A projector encapsulated into your dashboard sends a floating image at eye level onto your windshield.

Once the image leaves the projector, a series of mirrors direct, flip, and magnify the image, so you don't have to tilt your head or squint your eyes to understand the displayed information. An in-car HUD system gives you the option of moving around the information on your windshield as long as you can adjust the angles of the mirrors.

Related: Protect Against Keyless Car TheftSome car manufacturers decided to use a plastic window as the screen. Unlike the windshield, the plastic window has a uniform shape, and it's easier to obtain a clear image. You can even get an aftermarket HUD that uses this technology and fit it on your car.

While this option is usually less expensive, it comes with the disadvantage of a fixed position and a limited surface available to display information.

Headup display screen.
BMW Group/BMW Group

Also, a few systems use transparent phosphors placed on the windshield. When a laser shines on them, you will see information displayed on your windshield.

What Information Can You See With the HUD?

Car with HUD system going through a tunnel.
BMW Group/BMW Group

The information the HUD displays depends on the car manufacturer. Most of them will display your speed, gear count, speed limits, rev counter, and directions. Usually, you can select the shown data and even customize its color.

Some HUDs will go the extra mile and even show you information about G-forces, which you could consider useless if you're not a car enthusiast.

Future HUDs Will Incorporate Augmented Reality

As always, technology is evolving, and, eventually, the HUD system will no longer be just a method to project images onto your windshield.

Augmented Reality (AR) is making its way into the automotive industry, and it represents an upgrade for the HUD systems. AR is capable of integrating infrared cameras for increased visibility, radar systems to detect the car's speed that's in front of you, or to inform you about any on-road obstacles. And, of course, you should be able to display information from your phone onto the windshield.

Is the HUD Worth the Money?

There's no denying that the HUD comes with considerable safety benefits. Maybe it's not as important as other safety systems such as the anti-lock brake system (ABS), the electronic stability program (ESP), the automatic emergency braking system (AEB), or seat belts, but it might get there. The HUD, together with AR will show drivers obstacles or other dangers they can't yet see.

Related: Best Apps for Buying a New or Used Car

So if you are saving money for a new car, ask the sales representative about the HUD system. If it uses a plastic panel as its screen, it might force you to look down too much. Also, check its customizability level so you can set which information it shows. Especially if you are sharing the car with someone else and prefer different information layouts.

Driving With More Relevant Information

Now you're up to speed with in-car HUD basics. However, some tech and car enthusiasts think the HUD display will become more than a safety system. It could display real-time information all over your windshield about any museum, monument, or business you're driving by. This could mean schedule, rating, or even prices.