A middle-aged male patient, a long-distance bus driver, has been snoring at night for several years, accompanied by breath-holding and waking up; he feels that he sleeps well at night, falls asleep quickly and is not easily awakened at night; however, he always feels that he has not slept enough after waking up in the morning, with dry mouth, dizziness and headache. During the day, his energy decreases significantly, and his concentration and memory deteriorate. In the past year, he has been drowsy during the day and often feels sleepy when driving, which has led to many close traffic accidents. In March this year, he had another episode of drowsiness and involuntary sleep during driving, which finally led to a car accident, resulting in the death of a passenger. After the standard polysomnography examination, the patient’s sleep structure was disturbed, with more light sleep and less deep sleep, and the number of awakenings and microarousal index were high. In other words, although the patient thought he was “sleeping well”, he was actually sleeping for a sufficient length of time, but the quality of sleep was poor. The apnea hypoventilation index (AHI) during sleep was 75.7 breaths per hour; the average oxygen saturation during sleep was 91%, and the lowest oxygen saturation was 63%. He was diagnosed with “severe obstructive sleep apnea hypoventilation syndrome and severe sleep hypoxemia”. It is due to the patient’s long-term chronic intermittent hypoxia, resulting in disrupted sleep structure, poor quality, and significant daytime drowsiness that ultimately caused the tragic car crash. In recent years, more and more studies have shown that the health problems of drivers are the “black hand” behind the frequent occurrence of car accidents “road kill”, especially “sleep apnea syndrome”. The main manifestation of the disease is night snoring and daytime sleepiness; and the misconception that snoring is “sleeping well” often makes people ignore the dangers of breathing disorders during sleep. Japan, Brazil and other countries have passed legislation to “sleep apnea syndrome” into the driving license medical examination must be excluded and treatment of the disease, that is, suffering from the disease without effective treatment of people are not allowed to drive motor vehicles on the road. Although China does not have the relevant legislation, but the high rate of traffic accidents are always reminding everyone: for safety, please pay attention to your sleep!