Sandstorm animations on rural expressways: The impact of variable message sign strategies on driver behavior in low visibility conditions

摘要

Problem: Evolving sandstorms on rural expressways in desert countries impair drivers & rsquo; con -trast vision and increase the risk of serious crashes due to delayed speed adjustments. Intelligent Transport Systems (ITS) such as Variable Message Signs (VMS) conveying warn-ings can be activated to address drivers & rsquo; speed adaptation before entering a low visibility zone. To improve drivers & rsquo; understanding of the hazard, a sandstorm animation visualizing turbulent sand and its consequences was designed and compared with a general warning pictogram, which is applied if no specific weather pictogram is available. Moreover, mini-mum warning distances of the VMS to the low visibility zone were tested (e.g., 300 m or 500 m).Method: Sixty-three participants from the State of Qatar drove in a driving simulator through clear, transition, and low visibility conditions on a rural expressway. A repeated analysis of variances was conducted to examine the impact of the two on-road warning displays on driving behavior.Results: The results showed that the sandstorm animation was similarly effective as a gen-eric warning pictogram in reducing driving speeds before entering the transition and low visibility zone, irrespective of being displayed 500 m or 300 m away. However, the sand-storm animation resulted in consistent similar speed reductions within the low visibility zone, whereas the generic warning pictogram did either perform better or worse after sev-eral encounters with a sandstorm. Drivers did strongly agree that the animation is clearly referring to the issue of low visibility, which can be beneficial for recurring low visibility conditions.Practical applications: 1.) Displaying a sandstorm animation is beneficial for rural expressway sections with recurring degrading visibility and low traffic densities, whereas a warning pictogram can be more effective in speed reductions if drivers expect additional traffic hazards. 2.) Roadway authorities have the flexibility to activate a VMS sandstorm warning even for minimum warning distances.(c) 2021 Elsevier Ltd. All rights reserved.