Short answer

When designing HMIs for automated vehicles, consider using ambient lighting to not only alert drivers to takeover requests but also to subtly guide their visual focus to the most critical areas of the driving environment.

Field: Human Factors
Source: Information (2023)
Method: Driving simulator experiment
Evidence: Moderate effect

Ambient light HMIs, compared to auditory warnings, can guide drivers to focus their visual attention on the forward roadway more effectively after a takeover request in automated driving scenarios. This human factors research insight is drawn from a 2023 study published in Information. Using Driving simulator experiment, researchers explored how this design variable affects real-world outcomes. The key design takeaway: When designing HMIs for automated vehicles, consider using ambient lighting to not only alert drivers to takeover requests but also to subtly guide their visual focus to the most critical areas of the driving environment.

Study

Human FactorsRecentModerate effect

Ambient light HMIs improve driver attention focus post-takeover request in automated driving

Ambient light HMIs, compared to auditory warnings, can guide drivers to focus their visual attention on the forward roadway more effectively after a takeover request in automated driving scenarios.

Information · 2023

Key Findings

01Driver trust in automation was similar for both HMI conditions across most scenarios, except during a hard cut-in event.
02No significant differences were found in drivers' takeover performance or overall gaze distribution between the light-band and auditory HMIs.
03With the light-band HMI, drivers were more likely to direct their initial attention to the road center after a takeover request compared to the auditory HMI.

Application

Design takeaway

How to apply

When designing an HMI for a system that requires driver intervention, implement a visual cue (e.g., a subtle color change on the dashboard or a light strip) that not only signals the need for attention but also subtly directs the driver's gaze towards the primary visual field (the road ahead).

Project actions

01Consider testing different types of visual cues (color, intensity, pattern) for takeover requests.
02Investigate how the placement of ambient lighting affects attention direction.

Method & Evidence

AimTo compare the effectiveness of an ambient light HMI versus an auditory HMI in attracting drivers' attention and influencing their trust and perceived safety during SAE Level 3 automated driving, particularly during takeover requests.

MethodDriving simulator experiment

ProcedureParticipants engaged in a Non-Driving-Related Task (NDRT) during SAE Level 3 automated driving. They responded to a non-safety-critical transition of control and five cut-in events (one hard, four subtle). Takeover requests (TORs) were signaled by either a flashing light-band display or an auditory warning. Driver trust, perceived safety, takeover performance, and gaze distribution were assessed.

ContextSAE Level 3 automated driving in a driving simulator

Variables

IVType of HMI (Ambient Light vs. Auditory Warning)

DVDriver's initial gaze direction after takeover request, Driver trust, Takeover performance

CVSAE Level 3 automation, Non-Driving-Related Task (NDRT), Type and number of cut-in events, Driving simulator environment

Strengths & Limitations

Strengths

+Investigated a relevant and timely topic in automated driving.
+Used a controlled driving simulator environment to isolate HMI effects.

Limitations

Simulator studies may not perfectly reflect real-world driving. The specific design and context of the HMI are important.

Reliability & validity

The use of a driving simulator provides good control, enhancing internal validity. However, generalizability to real-world driving (external validity) might be limited. Reliability would depend on the consistency of the simulator and participant responses.

Think critically

To what extent does the novelty of ambient light HMIs influence the initial positive results, and would these benefits persist with long-term exposure?

Design Principles

"Visual HMI elements can be used to direct and prioritize driver attention in complex dynamic environments."

This insight is crucial for designing safer automated driving systems. By understanding how different HMIs influence driver attention, designers can create interfaces that minimize distraction and ensure drivers are looking in the right place at critical moments, thereby enhancing overall road safety.

What This Means for Your Design

Flashing lights on your car's dashboard are better than just beeps at making you look at the road when the car tells you to take over driving.

How to use in your project

1.Use this insight to justify the choice of an HMI in your design, arguing for the benefits of visual cues in directing user attention.
2.If your project involves a system that requires user intervention, consider how your HMI can guide user focus.

Add to My Project

Quick Cite

Paragraph starter

The research by Gonçalves et al. (2023) highlights the potential of ambient light HMIs to improve driver attention focus post-takeover request in automated driving. Their findings suggest that while both auditory and light-based warnings are effective at alerting drivers, ambient lighting can more effectively guide the driver's visual attention towards the forward roadway, a critical aspect for ensuring safety during transitions of control.

Source

Information

Is Users’ Trust during Automated Driving Different When Using an Ambient Light HMI, Compared to an Auditory HMI?

journal · 2023

View source

Questions About This Research

What does the research say about ambient light hmis improve driver attention focus post-takeover request in automated driving?: When designing HMIs for automated vehicles, consider using ambient lighting to not only alert drivers to takeover requests but also to subtly guide their visual focus to the most critical areas of the driving environment. Evidence: Information (2023).
Why does "Ambient light HMIs improve driver attention focus post-takeover request in automated driving" matter for design?: This insight is crucial for designing safer automated driving systems. By understanding how different HMIs influence driver attention, designers can create interfaces that minimize distraction and ensure drivers are looking in the right place at critical moments, thereby enhancing overall road safety.
How can designers apply this research?: When designing HMIs for automated vehicles, consider using ambient lighting to not only alert drivers to takeover requests but also to subtly guide their visual focus to the most critical areas of the driving environment.
What were the main findings?: Driver trust in automation was similar for both HMI conditions across most scenarios, except during a hard cut-in event.. No significant differences were found in drivers' takeover performance or overall gaze distribution between the light-band and auditory HMIs.. With the light-band HMI, drivers were more likely to direct their initial attention to the road center after a takeover request compared to the auditory HMI.
What research method was used?: Driving simulator experiment.
How strong is the evidence?: Evidence strength is rated Moderate effect, based on a 2023 journal from Information.
What should I do differently in my next project?: When designing an HMI for a system that requires driver intervention, implement a visual cue (e.g., a subtle color change on the dashboard or a light strip) that not only signals the need for attention but also subtly directs the driver's gaze towards the primary visual field (the road ahead).
What are the limitations?: The study was conducted in a driving simulator, which may not fully replicate real-world driving conditions. The specific nature of the NDRT and the cut-in events could influence results.