In-vehicle notifications to drivers during emergency road events: A conceptual design for Rubberneck and Sinkhole emergencies

• Drivers’ stress tendency affects their information needs. • Road operators can use this method to provide tailored emergency notifications. • Notifications for Sinkhole events should be more detailed than for Rubberneck. • Drivers would like an estimated end time for any emergency road event. • Drivers prefer receiving information in-vehicle notifications over other methods. We introduce a conceptual design for an internal Human-Machine Interface (iHMI) that allows highway operators to communicate directly with drivers during emergency events. The system adapts the notifications to the driver’s demographics and reported stress tendencies based on the RESIST module. Two emergency scenarios—Rubbernecking and Sinkhole—are used to illustrate the design. A Sinkhole emergency involves a partial road collapse that blocks traffic, while a Rubberneck emergency refers to traffic congestion caused by drivers slowing down to observe an incident outside their lane. Drawing on literature and expert interviews, we developed the emergency scenarios in a driving simulator, designed the iHMI notifications, and filmed videos from a driver’s perspective. A two-part online study was developed. It was distributed via social media and received responses from 108 drivers. First, respondents were categorized into support groups: “Need Support” (n = 20), “Would Like Support” (n = 49), and “Cool” (n = 39). Then, they viewed six short videos, varying by the event and the proximity to it (two events × three proximity levels) according to their assigned support group. Notification frequency differed among the support groups, with more frequent updates provided to those requiring greater support. After each video, participants rated the notifications they received. Results indicate an overall satisfaction with the frequency and detail level of the notifications for all support groups, with some variation by event type. Respondents were receptive to the concept of in-vehicle notifications suggesting that road operators should consider implementing adaptive iHMI systems to inform and support drivers during emergency events.