Crossing in the dark: Investigating the effect of vehicle kinematics and eHMI on older pedestrians' crossing behavior in a virtual reality experiment.

Older pedestrians adopted a different crossing strategy than younger pedestrians in non-deceleration trials by initiating crossing earlier to compensate for longer crossing duration.

• Participants were younger adults (18-35 years old) and older pedestrians (64-77 years old)
• In non-deceleration trials where older pedestrians decided to cross, they compensated for their longer crossing duration by initiating their crossing earlier than younger pedestrians
• If older pedestrians waited for more prominent deceleration before crossing, they waited longer than younger pedestrians
• The study used a cave-based pedestrian lab with virtual reality environments

Nighttime conditions caused pedestrians to feel less safe and behave more cautiously compared to daytime conditions.

• Pedestrians reported feeling less safe during nighttime crossings
• Pedestrians were less likely to cross during nighttime conditions
• Crossing initiation time (CIT) was longer during nighttime when there was no eHMI
• Both daytime and nighttime virtual environments were tested in the cave-based pedestrian lab

The eHMI (Slow Pulsing Light Band) decreased crossing initiation time for both younger and older pedestrians.

• The eHMI was a Slow Pulsing Light Band design
• eHMI decreased CIT for both age groups
• Despite the overall reduction in CIT, the eHMI was interpreted and used differently between younger and older pedestrians
• eHMI effects were evaluated across both daytime and nighttime conditions

An eHMI failure trial mainly affected younger pedestrians rather than older pedestrians.

• A specific eHMI failure trial was included in the experimental design
• The eHMI failure condition had differential effects by age group, with younger pedestrians being more affected
• Older pedestrians were less affected by the eHMI failure condition than younger pedestrians
• This finding suggests age-related differences in reliance on or interpretation of eHMI signals

AV kinematics including deceleration, speed, and time gaps were investigated as factors influencing pedestrian crossing behavior.

• The study manipulated AV kinematics variables: deceleration, speed, and time gaps
• Non-deceleration trials were compared to deceleration trials
• The prominence of deceleration influenced when older pedestrians decided to initiate crossing
• Kinematics and eHMI effects were evaluated across two age groups and two lighting conditions

Much existing AV-pedestrian interaction research has focused on younger pedestrians in daytime conditions, leaving knowledge gaps for older pedestrians and nighttime scenarios.

• The authors identified that prior research has focused on younger pedestrians' crossing behavior and experience
• Research has predominantly examined daytime conditions with optimum visibility
• AVs will interact with pedestrians of all ages and at all times, necessitating broader research
• This study addressed these gaps by including both younger (18-35 years) and older (64-77 years) participants and both daytime and nighttime conditions