Australian researchers have proved that visual clutter around roads, including prominent advertising, signs or billboards, can be a hazard for drivers – especially older ones.
They found that the distractions delay drivers’ abilities to detect a change around them – such as a vehicle changing lanes – by an average of half a second. Older drivers took the longest to react.
The work – from the Monash University Accident Research Centre (MUARC) – has important implications for the design and regulation of road environments and could lead to a new debate surrounding the need for tighter advertising restrictions along roads and highways.
‘Driving on a typical major road is a complex activity where drivers must process large amounts of visual information, which continuously changes, and make decisions at speed,’ said researcher Jessica Edquist.
Edquist conducted a series of tests with more than 100 drivers, almost half using MUARC’s high-technology advanced driving simulator. She found that drivers were distracted by billboards – they drove more slowly, took longer to change lanes in response to road signs and made more errors when changing lanes.
Older drivers in particular had difficulty detecting changes on the road and in following road-sign instructions in busy environments. The finding is crucial as, owing to an ageing population, there are more people aged 65-plus and more are staying on the road despite their age.
Edquist said that road authorities should carefully regulate billboards, declaring billboard-free distances around areas of high driver workload, such as intersections, merges and motorway exits.
‘Road authorities should also remove excessive signage and give advanced warning of hazardous situations with “priming” road signs to spread the cognitive workload. These adjustments are especially important for busy roads with many other vehicles, cyclists or pedestrians,’ she said.
Her work has already led to changes in Queensland and will provide evidence to bolster the arguments made by road authorities that roadside advertising should sometimes be restricted on safety grounds.
Edquist described three types of clutter: situational (mostly road traffic), designed (road markings and signage) and built (buildings, shop signs and advertising billboards, making backgrounds visually complex). They need to be considered together as they all contribute to driver workload, she said.