Prioritizing Safety or Traﬃc Flow? Qualitative Study on Highly Automated Vehicles’ Potential to Prevent Pedestrian Crashes with Two Diﬀerent Ambitions
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|DOI - pysyväislinkit|
|Tila||Julkaistu - 15 huhtikuuta 2020|
Interaction between drivers and pedestrians enables pedestrians to cross the street without conﬂicts. When highly automated vehicles (HAVs) become prevalent, interaction will change. Although HAVs manage to identify pedestrians, they may not be able to assess pedestrians’ intentions. This study discusses two diﬀerent ambitions: Prioritizing pedestrian safety and prioritizing eﬃcient traﬃc ﬂow; and how these two aﬀect the possibilities to avoid fatal crashes between pedestrians and passenger cars. HAVs’ hypothetical possibilities to avoid diﬀerent crash scenarios are evaluated based on 40 in-depth investigated fatal pedestrian crashes, which occurred with manually-driven cars in Finland in 2014–2016. When HAVs prioritize pedestrian safety, they decrease speed near pedestrians as a precaution which aﬀects traﬃc ﬂow due to frequent decelerations. When HAVs prioritize eﬃcient traﬃc ﬂow, they only decelerate, when pedestrians are in a collision course. The study shows
that neither of these approaches can be applied in all traﬃc environments, and all of the studied crashes would not likely be avoidable with HAVs even when prioritizing pedestrian safety. The high expectations of HAVs’ safety beneﬁts may not be realized, and in addition to safety and traﬃc ﬂow, there are many other objectives in traﬃc which need to be considered.