Applied Ergonomics 34 (2003) 177184Automobile seat comfort: occupant preferences vs. anthropometric accommodationMike Kolich*Department of Industrial accepted 28 September 2002AbstractAutomobile seat design specifications cannot be established without considering the comfort expectations of the target population. This contention is supported by published literature, which suggests that ergonomics criteria, particularly those related to physiology, do not satisfy consumer comfort. The objective of this paper is to challenge ergonomics criteria related toanthropometry in the same way. In this context, 12 subjects, representing a broad range of body sizes, evaluated five different compact car seats during a short-term seating session. Portions of a reliable and valid survey were used for this purpose. The contourand geometry characteristics of the five seats were quantified and compared to the survey information. Discrepancies were discovered between published anthropometric accommodation criteria and subject-preferred lumbar height, seatback width, cushionlength, and cushion width. Based on this finding, it was concluded that automobile seat comfort is a unique science. Ergonomics criteria, while serving as the basis for this science, cannot be applied blindly for they do not ensure comfortable automobile seats. r 2003 Elsevier Science Ltd. All rights reserved.Keywords: Automobile seat; Comfort; Anthropometry1. IntroductionThe ergonomics of seat comfort has been studied from a number of different perspectives (Zhang et al., 1996; Yamazaki, 1992). As a generalization, the current practiceistodesignautomobileseatstosatisfy ergonomicscriteria(synonymouswithergonomics guidelines). This approach is assumed to translate into positive consumer comfort ratings. For the purposes of this paper, there are two categories of ergonomics criteria. They are physiological and anthropometric. The physiological factors, which deal with muscles, vertebral discs, joints, and skin, have traditionally beenquantified using electromyography (Bush et al., 1995; Lee and Ferraiuolo, 1993; Sheridan et al., 1991), disc pressure measurement (Andersson et al., 1974), vibra-tion transmissibility (Ebe and Griffin, 2000), pressure distribution at the occupantseat interface (Kamijoet al., 1982; Hertzberg, 1972), and microclimate at the occupantseatinterface(Diebschlagetal.,1988). Ergonomics criteria related to physiology have, how- ever, come under scrutiny, particularly in the past decade. Reed et al. (1991), for example, described the automobile seat designers dilemma as the need for a balance between prescribing a physiologically appro- priate seated posture and accommodating a driver in a preferred posture. They reasoned that prescribed pos- tures sometimes compromise long-term comfort. Later, Reed et al. (1995), based on their preliminary data, highlighted the incompatibility between the traditional practice of designing automobile seatbacks to induce a large degree of lumbar lordosis (which is, according to Andersson et al., 1974, appropriate from a physiological perspective and the ideal of satisfying occupant-selectedspinal configurations (which, for some occupants, aremore kyphotic). Reed and Schneider (1996) verified this incompatibility in a follow-up study. Kolich et al. (2000), in the context of their investigation, came to a similar conclusion. These investigations all suggest that the human body has a great plasticity to adapt to a large variety of sitting conditions. For this reason, ergonomics*Corresponding author. Automotive Systems Group, Johnson Controls Inc., 49200 Halyard Drive, Plymouth, MI 48170, USA.Tel.: +1-734-254-5911; fax: +1-734-254-6277. E-mail address: michael.kolichjci.com (M. Kolich).0003-6870/03/$-see front matter r 2003 Elsevier Science Ltd. All rights reserved. PII: S 0003 -6870(02 )0 0142-4criteria based on physiology, because they do not ensure comfort, may unnecessarily limit automobile seat de- sign. Due in large part to Akerbloms (1948) work, ergonomics criteria related to anthropometry have long been considered a key aspect of comfortable seating. From this perspective, designers must ensure that arange of people, from small to large, fit in the seat. Ingeneral, automobile seat designs are specified by noting, for a target population, the constraining values of appropriate anthropometric dimensions (usually 5th percentile female and 95th percentile male). Comfortable accommodation in the lumbar region is best achieved through adjustability. This is, in the context of most applications, often impractical, due to the associated cost. According to Reed et al. (1994), the apex of the lumbar contour should be positioned between 105 and150mm from H-Point. As an aside, in the automotive seating industry, many anthropometric dimensions are referenced from H-Point, which is based on the hip point of a manikin that represents how medium-sized men sit in, and interact with, different vehicle seats and veh