Exploring False Warnings and Modalities for Emergency Vehicle Alerts and Their Impact on Driver Behavior

ObjectiveThis study explores the order effects in false alarms and the effect of warning modality when drivers receive an Emergency Vehicle Approaching (EVA) alert.BackgroundEVA alerts have the potential to decrease delays for emergency vehicles. However, false alarms and suboptimal warning designs can decrease warning effectiveness. Aligned with previous research, drivers should benefit from receiving an alert that is not visual.MethodA driving simulator study with 80 participants was conducted. During a 30-minute drive, the participants received three EVA alerts, one of which was false. One group received a false alert first, followed by a true alert. The other group had the opposite order. Both groups received another true alert before the experiment ended. Half of the drivers received auditory warnings, and the other half visual warnings.ResultsDrivers who received auditory warnings moved over more quickly compared to drivers who received visual alerts. There was an order effect of false warnings, suggesting that drivers who had received a false warning before they received a true warning were slower at moving over, compared to drivers who received a true warning in their first interaction. However, when the drivers received one true and one false warning each, there was no order effect in the third interaction.ConclusionBoth alert modality and false warning effects are important when implementing EVA alerts.ApplicationThis research should be used to understand the order effect of false warnings on in-car warnings. When designing in-car warnings, auditory warnings may be more effective.