Study the Effect of eHMI Projection Distance and Contrast on People Acceptance in Blind-Spot Detection Scenario

Abstract

External human-machine interaction (eHMI) road projections are a new feature for automotive lighting to improve vehicle communication with other road users. These modalities are used to draw users’ attention and awareness to specific situations. However, such advanced capabilities are still being debated to be used on the road in the context of whether or not such road projections can provide a clear and understandable message to road users in a specific scenario or lead to anticipation and change in the driving behavior. Therefore, it is necessary to investigate human factors aspects, such as the feeling of safety, useability, understanding, acceptability, and driver behavior. This study investigates the change in distance and luminance contrast and its effect on human driving behavior and acceptability in blind spot detection scenarios on the highway. A lab experiment with 12 participants is performed to analyze: understanding, satisfaction, usability, visibility, safety, workload, and driving behavior towards eHMI projection while varying projecting distance and luminance contrast. Video recordings and a designed questionnaire were used during the whole process. Results show that ego vehicle drivers prefer a projection distance between 5 to 10 m. However, a distance of 5 m is preferred by overtaking vehicle drivers in terms of visibility and safety. Luminance contrasts have no significant effect on the symbol’s visibility in 5 m and 10 m projection distances. In contrast, participants in overtaking vehicles feel difficult to understand the situation for 15 m condition, which increases their overall workload significantly (p < 0019). No significant effect is recorded in terms of change in driving behavior.

"It Must Be Gesturing Towards Me": Gesture-Based Interaction between Autonomous Vehicles and Pedestrians

“…In real-world scenarios, a vehicle's lights 10 meters away struggle to draw pedestrians' attention. [58] Additionally, it is crucial to ensure that pedestrians can perceive the signals the eHMI emits after drawing their attention to them. In the case of gesturebased eHMI, the recognition of actions plays a pivotal role in its effectiveness.…”

School Bus Lighting Effectiveness and Improvements: Results from a Driving Experiment

“…We also found that VMS was effective in increasing understanding, but not behavior; however, road experiments involving VMS were not available to confirm this from this study. However, when used in combination with a road projection, a VMS may prove to be useful in increasing understanding and could potentially function as an eHMI [32,35] for other uses as well.…”

“…Road projections may provide a range of benefits including enhanced safety [17][18][19][20] and improved driving experience [18,21], among others. Road projection technology has been proposed and/or studied for a variety of applications including parking assistance [22], displaying a stop sign or other road markings [23], displaying the width of the vehicle [24,25], navigation content [26], displaying warning messages [24], and communicating driving intention or warnings [20,[27][28][29][30][31], especially in the context of connected and autonomous vehicles (CAVs) as so-called external human-machine interfaces (e-HMIs) [32][33][34][35][36][37]. On the other hand, some research investigates whether there is a possibility that these types of projections could distract drivers [23,[38][39][40].…”