Perceptions of Two Unique Lane Centering Systems: An FOT Interview Analysis 2020-01-0108
Objective: The goal of this interview analysis was to explore and document the perceptions of participants in a field operational test (FOT) including two unique lane centering systems (S90’s Pilot Assist, and CT6’s Super Cruise). Both systems offer similar functionality on paper (continuous longitudinal and lateral vehicle control), but have drastically different HMI implementations.
Methods: Twenty-four drivers (16 male, 8 female) in the Greater-Boston Area participated in an FOT study, in which each participant drove one of two vehicles for a month. Upon vehicle return, drivers took part in a 30 to 60-minute semi-structured interview to record their perceptions of the vehicle’s various ADAS systems. Transcripts of the interviews were coded by two researchers to assign each participant’s statements to specific vehicle technologies as well as to attribute perceptions to each statement. The analyses in this paper focus on adaptive cruise control (ACC) and lane centering technologies.
Results: Participants cite perceived positive benefits, such as increased safety and comfort provided by lane centering and adaptive cruise control systems, but also cite concern over the possibility of increased inattention to the driving task. Driver perceptions of adaptive cruise control were similar between vehicles. When comparing perceptions of lane centering between vehicles, however, there were distinct differences. The proportion of drivers that cited benefits associated with comfort (enjoyment, reduced stress, increased comfort) was larger for those who experienced Super Cruise (a hands-off-wheel system) than for those who experienced Pilot Assist (a hands-on-wheel system). However, the proportion of drivers that cited a redundant safety benefit provided from the use of lane centering was larger for those who experienced Pilot Assist than for those who experienced Super Cruise. Overall, perceptions of drivers who used Pilot Assist indicate they were more likely to view the system’s role as back-up for the human driver, whereas those for drivers who used Super Cruise were more likely to view their role as back-up for the system.
Conclusions: While functionally similar, the two lane centering systems studied (Pilot Assist and Super Cruise) were perceived quite differently by participants. Results suggest that drivers’ comprehension and expectation of these systems’ behavior are strongly influenced by their HMI design, specifically in terms of their difference in hands-on versus hands-off-wheel implementation. The perceived role of the driver – as either a fallback driver or as the sole driver - may be influenced by this HMI design implementation. It is important to highlight the consequences of different design implementations for lane centering systems in order to provide guidelines for future HMIs and to better match designer with driver expectations.
Steven Landry, Bobbie Seppelt, Luca Russo, Bruce Mehler, Linda Angell, Pnina Gershon, Bryan Reimer
Massachusetts Institute of Technology, Touchstone Evaluations Inc