How do we sleep? Towards physical requirements for space and environment while travelling
研究了189名参与者的睡眠姿势，发现74%侧卧，49%双腿弯曲侧卧，提出旅行中床铺尺寸200×90厘米足够，过夜时171×76厘米可能可行，并强调黑暗、适宜温度和安静环境的重要性。
To establish guidelines for sleeping space in vehicles, the sleeping postures of 189 participants are studied, 105 of them were asked to take the position in which they fall asleep and 84 have been asked to assume the position in which they lie most of the time. Seven percent slept on the stomach, 19% on the back and 74% on the side and 49% slept on the side with both legs flexed. For all participants a bed size of 200 × 90 cm will do. It is discussed that for one night while travelling a bed size of 171 × 76 cm might be sufficient as it results in a reasonably good sleep according to another study and in almost half of the cases in this study people sleep on the side with both legs folded. Apart from the sleeping space for a good sleep, attention is needed for a dark environment with a good temperature and relative silence.