Do Not Adjust Your Set! How a Visual Alert Reduced Unnecessary Human Intervention in an Automated Vehicle

Human remote operators, teaming with Automated Vehicles (AV), will need to be provided information from the AV to make decisions on how, or when, to intervene in the AV operations. As an extension to research into how many AVs an individual can successfully monitor, the authors designed and implemented a human machine interface (HMI) that provided key information on the probability that an AV might need an intervention from a remote operator. A key element of that interface was the provision of feedback indicating if a vehicle was stationary, provided in the form of a timer, and a visual alert given 10s after the vehicle came to a halt. An experiment was conducted into the efficacy of this visual alert, by on occasion removing it from use. It was expected that the absence of the visual alert would lead to more incidents where a remote operator missed a requirement to intervene. However, the results indicated that in the absence of the alert the remote operator was more likely to intervene. This paper examines how elements of the HMI design affected the participants decision to intervene in AV operations, and concludes that by offering transparent system-state feedback, the HMI effectively counters the innate psychological pressure to act, reassuring the operator that inaction can be an appropriate and system-approved response.