What is a head-up display (HUD)?

A car’s head-up display, commonly abbreviated to HUD, is a transparent screen that projects key information, such as the vehicle’s current speed and navigation guidance, into the driver’s line of sight so that their attention is not distracted from the road.

This technology is gradually finding its way into more and more mainstream cars, with many more affordable cars now available with HUD offered as an optional extra, if not fitted as standard.

Early systems were rather simplistic, but the latest generation of HUDs have full colour displays and even more advanced features such as road sign recognition. Opt for a more premium model such as a Mercedes and you can even have Augmented Video Navigation.

What information does a head-up display show?

Your speed is usually the largest piece of information on your head-up display, shown as a precise number and usually interchangeable between mph and km/h.

In cars fitted with cameras that can read speed limit signs, you'll often see the limit displayed for the road that you’re currently driving on. Sometimes this information can be taken from the car's sat-nav, too.

On that matter, if your car is equipped with a sat-nav, then it's normal for directions to be displayed on the head-up display too. Typically, they won't appear when you're just following a road, but will be displayed when you're approaching a junction or exit that you've got to take.

The images are usually very simple: such as a single arrow, or an outline of a roundabout, so any instructions can be understood in an instant.

Some systems, such as those used by BMW, also include entertainment functions into the head-up display. It will display radio stations or your song list as you scroll through using a button on your steering wheel.

What types of head-up display are there?

There are two main types of system. The cheapest and most common has a small screen that rises from the dashboard ahead of the driver onto which the information is projected. You might see this referred to as a combiner type HUD.

This pop-up solution is not particularly attractive or sophisticated, but it is effective and easily adjustable to suit the driver. It's an option on cars such as the Mini Hatchback, Mazda 3 and Ford Focus.

The second type beams the information straight onto the windscreen from a small module on top of the dashboard. This way, there's no pop-up screen cluttering the top of the dashboard. BMW uses this kind of system in many of its cars.

As well as looking less clunky, this type of integrated system gives the impression that the information is being displayed on the road ahead. This prevents the driver from having to refocus their eyes from the HUD, and back again up to the road. The driver can also adjust the position of the projection should they desire.

In a similar fashion to sat-navs, there are a handful of aftermarket HUD systems. Products by Navdy and Hudway claim to bring HUD technology to any car. Both are of the pop-up type, and while the former is a standalone system that costs several hundred pounds, the latter comes in at around £50 because it projects its information from a smartphone, rather than a standalone screen. There are some apps, too, but this involves fixing your phone to the dashboard. They're not particularly effective and aren't all that safe, either.

What are the safety implications of a head-up display?

A head-up display puts key information in front of the driver, so they spend more time looking at what's in front of them.
In an experiment which assessed the reaction times of drivers identifying pedestrians while checking their speed (head-up and head-down units were both used), findings from a study showed HUDs presented a time advantage over head-down systems, which resulted in drivers identifying more pedestrians.

These findings would seem to suggest that buying a car with a HUD makes for safer motoring. However, critics say that it can become a distraction, on top of the multiple other screens that occupy the front of modern cars.

Some believe that another screen won’t help drivers keep their attention on the road. They argue that being able to shuffle through songs or see phone notifications is just another distraction.

Cars with head-up displays

A large number of manufacturers now offer a HUD, although few manufacturers fit the equipment as standard. Below is a table showing which makes and models come with the option of a HUD.

This list is not exhaustive, as car manufacturers introduce these frequently both in new models and in mid-life updates. To be sure, we recommend that you check the spec sheet of any individual car that has caught your eye.