Robert E. Llaneras

Distracted driver performance to multiple alerts in a multiple-conflict scenario

Objective: We investigated whether collision avoidance systems (CASs) should present individual crash alerts in a multiple-conflict scenario or present only one alert in response to the first conflict. Background: Secondary alerts may startle, confuse, or interfere with drivers’ execution of an emergency maneuver. Method: Fifty-one participants followed a pickup truck around a test track. Once the participant was visually distracted, a trailing sedan repositioned itself into the participant’s blind spot while a box was dropped from the truck. Participants received a forward collision warning (FCW) alert as the box landed. Twenty-six drivers swerved left in response to the box, encountering a lateral conflict with the adjacent sedan. Half of these 26 drivers received a lane-change merge (LCM) alert. Results: Drivers who received both the FCW and LCM alerts were significantly faster at steering away from the lateral crash threat than the drivers who received only the FCW alert (1.70 s vs. 2.76 s, respectively). Drivers liked receiving the LCM alert, rated it to be useful, found it easy to understand (despite being presented after the FCW alert), and did not find it to be startling. Conclusion: Drivers who are familiar with CASs benefit from, and feel it is appropriate to generate, multiple alerts in a multiple-conflict scenario. Application: The results may inform the design of CASs for connected and automated vehicles.

Strategies to Assist Drivers in Remaining Attentive While Under Partially Automated Driving: Verification of Human–Machine Interface Concepts

Visual inattention is a major concern with partially automated driving systems that assume vehicle steering functions. The safety concept for these systems capable of maintaining vehicle lane position and headway depends on an attentive driver who detects and appropriately responds to objects and events that are beyond the limitations of the sensors. Embedded within a proposed system are features designed to help drivers perform these functions and remain attentive to the driving environment. This study served to validate human–machine interface (HMI) strategies and concepts that can be applied to production-intent partially automated system HMI to achieve intended safety goals in assisting drivers to maintain attention to driving. Previous validation efforts, conducted as part of a NHTSA study, proved insufficient for verification of these driver performance functions since they relied on an incomplete version of alternative HMI concepts. The current study, with a sample of 25 licensed drivers, used approaches that more closely approximated the potential production-intent partially automated HMI concepts, including the introduction of consequences for failing to respond to alerts. Work was performed by using an advanced prototype capable of mimicking the basic functions afforded in a partially automated system. Driver responses to unexpected lane drift events were also examined. Results found that HMI concepts that introduce consequences for driver nonresponse situations substantially increase driver compliance to system cues, prompts, and alerts. Results of this study suggest that the potential production design partially automated system HMI concepts can assist drivers in maintaining their attention to driving.