Typically, drivers in a level 3 automation environment need at least 8s following a manual take-over request to achieve appropriate levels of situation awareness. Studies that have derived this time estimate use general audio alerts that suggest a transfer of control from the automation to the driver might be required. The current experiment examined if improvements in younger drivers’ situation awareness might be observed in as little as 4s prior to when a latent hazard might materialize and a transfer of control occurs if more specific audio alerts are used. Younger drivers were randomly assigned to 1 of 4 between-subjects cue conditions: 1) a general cue condition, 2) a condition that described the risky feature(s) of the roadway and the location of those features, 3) a condition that contained information regarding the actual identity of the threat and the required behavior, 4) a combination cue condition (both environment and threat cue). Eye-movements were recorded as drivers completed six scenarios in a simulated automated driving experiment. The results showed that audio cues that contained information regarding risky roadway features increased the detection of latent hazards by almost 40% compared to when a general cue or a threat cue was used. Performance with the combined cue was no better than performance with the environment cue. The environment cue gives drivers the critical seconds needed to mitigate a potential crash. Results are informative regarding which types of alerts to use to inform drivers of upcoming hazards. (Author/publisher)
Abstract