Can head up displays really improve driver safety ?

Car makers offer some interesting equipment options that are said to increase driving safety. One of those features is a head up display, which shows the driver essential information, such as the speed and turn-by-turn directions, without having to take the eyes off the road.

This is a benefit that is commonly pitched by car companies, as, in theory, it would allow the driver to be more focused on what's ahead rather than be distracted by a smartphone or navigation system.

However, a University of Toronto report contradicts this assertion, claiming that, in practice, HUDs are distracting and "a threat to safety" because they force drivers to focus on two different things at once: the road ahead and the windshield.

"Drivers need to divide their attention to deal with this added visual information", says Ian Spence, who is a professor at the University of Toronto's Department of Psychology. "Not only will drivers have to concentrate on what’s happening on the road around them as they’ve always done, they’ll also have to attend to whatever warning pops up on the windshield in front of them".

Like I said in the opening paragraph, HUDs can indeed show different pieces of information. The amount of information they are capable of displaying depending on how complex they are, or how expensive the car is, basically. They are, however, not a new technology, as BMWs, for instance, have had HUDs as an option as early as the last decade - they can be commonly seen in the old 5 Series E60 generation, which entered production in 2003.

As car technology advances, the amount of information that HUDs can show will naturally increase. This increases risk, according to the research, as drivers will more easily miss what is ahead while analysing the information show by the HUD.

To determine the impact, the report says that test subjects were shown between one and nine randomly placed spots and, on some trials, also a black square. When both appeared, the square was missed once in 15 times. However, when the number of spots increased, the square was missed once in 10 times.

If you think of the square as an incoming car, then there's a one in 10 chance a driver might not see it in time while looking at a modern HUD. "The accuracy of the number of spots reported also diminshed [sic] as the number of spots increased, suggesting that as a primary task becomes more demanding both tasks [driving and analyzing HUD information] compete with and interfere with each other", adds the report.

What's more, drivers are also unable to distinguish important alerts from non-critical information, suggesting that even if car makers label everything that is displayed well, drivers will still have attention issues.

To test this, the researchers used different shapes (triangle, square or diamond) among spots, and asked the subjects to identify them and the number of spots. "Observers made both judgements more slowly when the shape appeared among the spots by as much as 200 per cent", says Spence. "The two visual tasks interfered with each other and impaired both reaction speed and accuracy".

"Missed warnings and slowed reaction times present real threats to safety", adds Spence. "Furthermore, this rivalry for the driver’s attention is most likely to occur when the driving environment is demanding".

But, while the research is clear in its findings, I think driving safety should be looked at as a whole and not in isolation. Indeed, focusing at the road ahead is much safer than having to divide the driver's attention between it and the windshield, but the latter scenario beats taking their eyes off the road completely to look at who texted, the speedometer, or glance at the navigation system to see when and where their next turn is.

As technology evolves, and not just in the automotive field, consumers will want to embrace certain things, like smartphones in the car. This cannot be reversed or effectively stopped, but cars can be designed around it so that consumers do not have to make some dangerous choices.

Some people will always text and drive, and there is nothing that can be done about it, but with the car reading their texts aloud and allowing them to reply by voice they have a better chance at staying safe while on the road and keeping others safe as well.

Photo Credit: BMW