Human-centred design the route to improving road safety

Emeritus Professor Michael Regan, from the UNSW School of Civil and Environmental Engineering, is a psychologist specialising in transportation human factors. Professor Regan believes traffic control devices, including destination signs, warning signs and traffic lights, need to be designed from a human-centred perspective to be effective.

“Our road and transport environment is designed to help us to get from point A to point B. However, there is a fine line between what should be capturing our attention to assist us along that journey and what is a risk of being a distraction. For example, things such as advertising billboards along highways draw the driver’s attention to whatever is being promoted in the ad. But at the same time, they are a source of distraction and may instead draw the driver’s attention away from things that are critical for safe driving — such as being focused on the road ahead,” Professor Regan said.

The cockpit design of cars has changed over the years, with a shift to more interactive features and functions such as touch screen displays and Apple CarPlay. While these are meant to enhance the driving experience, they can often be a distraction for the driver. Professor Regan noted that approximately 70% of distractions are within the vehicle, adding that actions such as selecting radio stations with touchscreen displays, entering destinations into navigation systems or reaching for something in the glove box while the vehicle is in motion are all distractions that pose a huge risk to the driver.

“If you take your eyes off the road for two seconds, it’s been shown that you double your risk of a collision. Any longer than two seconds, and the risk of a crash increases exponentially. As vehicle cockpits inherit more functionality and become more interactive, we need to ensure the driver’s safety is not compromised,” Professor Regan said.

For traffic control devices to be effective, they must be conspicuous and legible, with a comprehensible message. Working in the UNSW Research Centre for Integrated Transport Innovation (rCITI), Professor Regan said that when a traffic light or sign lacks one or more of these characteristics, it can instead become a distraction. Professor Regan added that signs need to be credible and widely accepted by road users, otherwise they will be ignored.

“Some traffic lights or signs aren’t obvious to drivers because they’re hidden behind a tree or there’s something blocking it. This encourages drivers to adopt compensatory visual scanning strategies to try to see them, which takes their eyes off the road for longer than is necessary. To capture the attention of the driver, signs must not have anything obstructing the messaging, so that it is visible to the driver — and the messaging must be crystal clear,” Professor Regan said.

The Australian New Car Assessment Program (ANCAP) gives star ratings for the vehicle’s ability to protect the occupants in the event of a crash. A higher rating is awarded for vehicles with active safety systems, such as autonomous emergency braking, which assist the driver in preventing or minimising the effects of a crash with pedestrians, cyclists or vehicles. Professor Regan believes a similar system must be developed to rate the safety of the design of roads, from a human-centred perspective.

“Some drivers may choose to drive on certain roads which are rated safer than others because, among other things, they know they will contain signs and signals that are conspicuous, legible and comprehensible, meaning they are less likely to become confused and distracted,” Professor Regan said.

Ideally, all road and transport environments would be designed from a human-centred perspective, to minimise human error and optimise overall safety. However, humans will still be prone to conditions that may degrade their driving performance and safety. Professor Regan noted that road users who are cognitively distracted — for example, when talking on their mobile phone about something complex or emotional — may see a traffic light change colour but not respond to it. Professor Regan refers to this as intentional blindness; a look-but-fail-to-see phenomenon that is an issue for drivers and pedestrians, too.

“Drivers and other road users will continue to be prone to distraction, fatigue and other human conditions. However, there is much that can be done, through good human-centred design, to enhance their safety and prevent crashes,” Professor Regan said.

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