The difference can be invaluable. One American study revealed that if a driver's eyes wander off the road for more than two seconds then the chance of an incident doubles. Two seconds might not sound like much but, at 70mph, you'll have travelled over 200 feet - about the length of 14 cars. So, by enabling the driver to remain focused on the road, a HUD neatly helps counter this issue.
HUDs were first developed, like the origin of much automotive technology, for aircraft. In the early 1940s, engineers began projecting extra information, like radar images, onto the windscreen of night fighters - and the concept swiftly progressed to include the likes of artificial horizons and bomb aiming markers.
As the hardware advanced, it caught the attention of General Motors. Consequently, early design renders for its 1965 Mako Shark II concept - with its aircraft-themed interior - reputedly featured a HUD. The idea remained on the drawing board, however, until a prototype was tested in 1968. The XP-856 Aero Coupe concept, displayed in 1969, also featured a HUD. Complexity and cost, presumably, prevented the idea progressing any further.
Having merged Hughes with its established Delco Electronics arm, GM ordered that the newly formed Hughes Electronics Corporation develop a HUD for the upcoming fifth-generation Cutlass Supreme. It was to feature a new front-wheel-drive platform and modern engine options, and a HUD would be the technological icing on the cake.
Finally, in May 1988, the first production HUD was unveiled in the Oldsmobile Cutlass Supreme Convertible Indy 500 Pace Car, 50 of which were offered to selected customers. The system was then made available as an option elsewhere.
GM just beat Nissan to the punch, too; Nissan had finished developing its first HUD in December 1987 but it didn't appear on the Maxima and 240SX options list until late 1988. Toyota soon joined the party, unveiling its HUD-equipped Crown Majesta in 1991.
HUDs aren't restricted to the realm of flagship models these days, mind, as the technology has trickled down through many manufacturers' model ranges. Okay, so some of the chintzy pop-up plastic ones aren't quite as technologically gratifying, but the benefits are the same.
Got an older car? Well, you need not feel left out - as there are several aftermarket and app-based solutions, many of which work well. Great, speaking from experience, for when your speedometer takes an unexpected leave of absence.