How many daily hours of sleep does an adult need to maintain alertness? Before you start the test, please answer the question below regarding your insurance status. Without insurance you will not be able to drive in Ohio Do you currently have car insurance? Yes I have insurance. Great, you're all set! Click here if you still want to compare rates. No, I need insurance and I want to compare options. Question How many daily hours of sleep does an adult need to maintain alertness? Answers Six to seven Seven to eight Eight to nine Four to five Explanation Being properly rested is essential to the safe operation of a CMV. To maintain alertness, most people need eight to nine hours of sleep per night. This questions appears in the following tests: Alaska Class A Knowledge Test