Sentence:  After the fuel economy crisis of the 1970s, the U.S. automotive industry began placing more emphasis on both the aerodynamics and <WSD>ergonomics</WSD> fields to satisfy customers' energy-saving and comfort/convenience needs. ... <WSD>Ergonomics</WSD> involves "fitting the equipment to the people (or users)." This means the equipment should be designed such that people (population of users) can fit comfortably (naturally) within the equipment and they can use the equipment without any awkward body postures, movements, or errors. 
Meaning of the word marked with <WSD> tags:  The science of the design of equipment, especially so as to reduce operator fatigue, discomfort and injury. (from c. 1950.)