title: Use patterns among early adopters of adaptive cruise control.
abstract: OBJECTIVE
  The objective of this study was to investigate use patterns among early adopters of adaptive cruise control (ACC).
  
  
  BACKGROUND
  Extended use ofACC may influence a driver's behavior in the long-term, which can have unintended safety consequences.
  
  
  METHODS
  The authors examined the use of a motion-based simulator by 24 participants (15 males and 9 females). Cluster analysis was performed on drivers' use of ACC and was based on their gap settings, speed settings, number of warnings issued, and ACC disengaged. The data were then examined on the basis of driving performance measures and drivers' subjective responses to trust in ACC, understanding of system operations, and driving styles. Driving performance measures included minimum time headway, adjusted minimum time to collision, and drivers' reaction time to critical events.
  
  
  RESULTS
  Three groups of drivers were observed on the basis of risky behavior, moderately risky behavior, and conservative behavior. Drivers in the conservative group stayed farther behind the lead vehicle than did drivers in the other two groups. Risky drivers responded later to critical events and had more ACC warnings issued.
  
  
  CONCLUSIONS
  Safety consequences with ACC may be more prevalent in some driver groups than others. The findings suggest that these safety implications are related to trust in automation, driving styles, understanding of system operations, and personalities.
  
  
  CONCLUSIONS
  Potential applications of this research include enhanced design for next-generation ACC systems and countermeasures to improve safe driving with ACC.
authors.affiliation: Dept of Industrial and Systems Engineering, University of Washington, Seattle 98195, USA.
authors.forename: Huimin
authors.initials: H
authors.lastname: Xiong
authors.forename: Linda Ng
authors.initials: LN
authors.lastname: Boyle
authors.forename: Jane
authors.initials: J
authors.lastname: Moeckli
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Dow
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Brown
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D001288:Attention; D001331:Automation; D001334:Automobile Driving / Q000523:psychology*; D001336:Automobiles; D003198:Computer Simulation; D004867:Equipment Design; D005260:Female; D006801:Humans; D007484:Iowa; D008297:Male; D008875:Middle Aged; D011930:Reaction Time; D012309:Risk-Taking; D013647:Task Performance and Analysis