Effects of the roadside visual environment on driver wellbeing and behaviour - a systematic review

The view that drivers have from the road can be enjoyable or disturbing, stressful or relaxing, distracting or fatiguing. Road planning guidelines balance aesthetical and safety considerations but are rarely grounded on empirical evidence. This paper reviews evidence on the effects of the roadside visual environment on the wellbeing and behaviour of drivers, focusing on natural and built elements external to the road, i.e. excluding road geometry, design, conditions, and users. Standardised information was extracted from 50 studies. These studies have used experiments involving participants watching videos or driving a simulator or instrumented vehicle, usually with unrepresentative samples (mostly males, young age groups, and students). Most evidence is related to the driving task (e.g. distraction, fatigue), not to wider aspects of driver wellbeing (e.g. stress recovery), and to safety issues, not aesthetical ones. There is increased evidence for monotonous views (linked to fatigue), roadside vegetation (linked mainly to a reduction of stress and risky driving behaviours, but depending on the characteristics of the vegetation) and advertisements (linked to distraction, but depending on advertisement type and other variables). A few studies have looked at other elements of the built environment (memorials, drones, wind turbines, utility poles), with mixed evidence on distraction and safety behaviour. The links between continued exposure to certain types of views and car commuter stress have not been studied. There is little evidence for developing countries or differences by gender, visual impairment, trip purpose, and type of vehicle.