Browsing by Author "Rossi-Alvarez, Alexandria I."
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- Allusion 2: External Communication for SAE L4 VehiclesRossi-Alvarez, Alexandria I.; Klauer, Charlie; Schaudt, Andy; Doerzaph, Zac (Safe-D University Transportation Center, 2023-12)With SAE Level 4 and above (L4+) Automated Driving Systems (ADSs) being integrated on roadways, stakeholders worldwide are developing external communication systems for other road users to communicate effectively. Most research on SAE L4+ ADS external communication has used simulators or virtual reality platforms to assess driver/road user knowledge, opinions, and attitudes via survey metrics evaluating a single L4 vehicle. However, it is vital to understand perception of external communication in real-world conditions and with multiple SAE L4+ ADSs present. This research explored how the presence of multiple SAE L4+ ADSs with external communication displays affected participants’ crossing decisions. A within-subject design assessed participants’ understanding of SAE L4+ ADS intentions. Results indicated that the presence and condition of external human-machine interfaces (eHMIs) did not influence willingness to cross. It was difficult for participants to focus on the eHMI when multiple vehicles competed for their attention. Participants typically focused on the vehicle that was nearest and most detrimental to their crossing path. Scenario type caused participants to make more cautious crossing decisions but did not influence willingness to cross. This study implies that eHMI with two patterns may still require simplification for pedestrians to interpret in a complicated traffic environment.
- Impact of Highly Automated Vehicle (L4/5 AV) External Communication on Other Road User BehaviorsRossi-Alvarez, Alexandria I.; Grove, Kevin; Klauer, Charlie; Miles, Melissa; Schaudt, Andy; Doerzaph, Zachary R. (SAFE-D: Safety Through Disruption National University Transportation Center, 2022-10)The advancement of SAE Level 4+ Automated Vehicles (L4/5 AVs) has led numerous stakeholders to develop external communication systems for these vehicles. Most research on vehicles emulating these displays has been conducted using one vehicle. However, it is vital to understand how communication to vulnerable road users (VRUs) is affected when multiple L4/5 vehicles are present. This study examined how L4/5 AVs can best communicate their intentions (e.g., turning, stopping, yielding) to VRUs and drivers of conventional vehicles. Subjective and objective data was collected to assess road user responses to two vehicles emulating L4/5 displays, from both a passenger and pedestrian perspective. Participants with no prior knowledge of the experiment’s design or intent experienced three light patterns that provided information regarding L4/5 AVs’ intent to slow/stop, begin, and travel with simulated automation active. Overall, participants were overwhelmed by multiple vehicles with different light bars in their crossing vicinity and found it difficult to prioritize attention. These results have implications for future design of external communication displays on L4/5 AVs. Training may be necessary for road users, given the relatively low percentage of participants who understood the meaning of these displays after multiple exposures and participants’ confusion in where to look and how to interpret the intention of the displays when multiple vehicles were present.