Head-up display (HUD) technology

From cockpit to driver’s seat

Head-up display (HUD) was first developed during World War I to help fighter pilots lock in on their targets. Basic flight information for altitude, air speed, compass, and artificial horizon indicators was later added to reduce the need for pilots to look down at the instrument panel. That same technology was transferred to drivers in 1988 when General Motors installed the first HUD system in one of their luxury cars, and now with advances in technology, HUD systems are readily available from car manufacturers and aftermarket suppliers.


Behind the screen: How HUD works

A HUD is an ingenious device that improves safety. A HUD system can be included during manufacture or installed aftermarket. Essentially, automotive HUDs consist of three parts:

  • Picture generation unit (PGU)—processes data from multiple sources for projection
  • Projector—generates and directs image
  • Combiner—the surface where the image is projected (usually the windscreen)

Because the unit is placed on the dashboard and the image projected on the windscreen within such a confined space, a series of mirrors and lenses within the PGU reflect, refract, focus, and magnify the image for display. The projected image travels up the windshield on an optical path between two planes of treated laminated glass, where it is displayed on the windscreen at the appropriate eye level.


The significance of HUD

Increasingly, HUD systems are becoming indispensable. At the most basic level, HUDs improve driver well-being by:

  • Providing assistance through adverse driving conditions
  • Increasing driver awareness of vehicle performance and current road events
  • Reducing stress with advancements in satellite navigation information
  • Advising on traffic conditions, local parking options, and nearby fuel availability
  • Enriching the traveling experience with information on nearby restaurants, other entertainment opportunities, and special offers
  • Providing entertainment and enrichment via radio channels, podcasts, or music
  • Allowing hands-free communications


Keeping drivers’ eyes on the road

The two most important benefits of HUD technology are reduced driver distraction and increased driver safety. Drivers keep their eyes on the road while viewing critical vehicle data. A plethora of information can be displayed at eye level :

  • Map displays with current positioning
  • GPS directions
  • Road conditions such as speed limit, detours, accidents, or weather-related issues
  • Vehicle information, including mileage, fuel, engine temp, and system warnings
  • Warnings about poor driving behavior such as sharp turns, sudden lane shifts, and even alerts about driver fatigue


HUD working principles

Driving is a highly complex activity, requiring the abilities to focus on the road and multitask. Drivers must make split-second decisions. In the time it takes to look away from the road and back, the driver goes through the following process:



Keeping drivers focused

Response time is critical. Driving involves how quickly a driver can react to events as they occur. Another car’s unsignaled lane change, a pedestrian, a pothole, or black ice all require a quick response. The minute a driver looks away from the road, an unforeseen event can occur. In the time it takes to refocus after going from road to instrument panel or somewhere else in the car back to the road, a few seconds could prove costly.



In time, it’s possible that HUD will replace the technology normally displayed on the dashboard, referred to as head-down display (HDD). Comparison studies show drivers relying on HUD technology:

  • Lessen “focal accommodation time” as their eyes are already on the road
  • Respond quicker to urgent events, including earlier detection of road obstructions
  • Maintain consistent awareness and control of speed within posted speed limits
  • Experience less mental stress, especially easier to use for first-time users
  • Spend less frequency and duration glancing down
  • Improve understanding of vehicle’s surrounding space particularly under low visibility conditions


Advancements in HUD technology

HUD technology has seen vast improvements since it was first introduced to automobiles, including:

  • Capability to adjust to ambient light, making images clear whether it’s day or night
  • Improved communication process between driver and vehicle systems such as fuel-efficient hybrid engines, proximately sensors, rain-detecting windshield wipers, built-in multimedia entertainment, and power-adjusting all-wheel drive systems
  • Connectivity to hands-free devices such as Bluetooth, navigation systems, voice-activated commands, and on-demand audio


So what does the future hold for HUD?

Two words: Augmented Reality (AR).
Check back with us next month for an article on how soon we can expect real-time visual information with HUD technology.

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