An eye-tracking study of the effects of dimensions of speed limit traffic signs on a mountain highway on drivers' perception

Signs control and regulate traffic, anticipating potential dangers, prescribing correct behaviors, and disambiguating likely conflicts in priority. In Brazil, traffic accidents on highways located in mountain rural areas are mainly related to the design of roads and speeding, rather than to the impact of traffic flow. Since drivers highly depend on their visual perceptions for adopting driving behaviors, this study analyzes driver perception during a trip and the response of this parameter to changes in the diameter of vertical speed limit signs in a driver simulator equipped with an eye-tracking system. The objective was to investigate whether an increase in the plate size would enhance driver perception and influence drivers' compliance with speed limits. Fifty-five volunteers were asked to drive twice on a 10-km mountain route, after which one of the diameters, namely 75, 100, 120, and 150 cm, used according to several Brazilian and American standards, was randomly chosen. The results showed the size of the traffic signs did not affect dependent variables number of fixations, percentage of perceived signals, time of observation, perception distance, and non-compliance with the speed limit. The most significant result was the relationship between speed variability and guided round, since the driver's performance was improved with the distance along the studied stretch. The outcomes can be useful for the development of strategies that manage speeding on roads by improving and implementing low-cost interventions in low-income countries.

Automated summary

This study analyzed driver perception and response to changes in the diameter of vertical speed limit signs using a driver simulator equipped with an eye-tracking system. The results showed that the size of the traffic signs did not affect driver behavior and compliance with speed limits, but driver performance improved with distance traveled. These findings can be useful for managing speeding on roads by implementing low-cost interventions.