Final answer:
It is important to turn off your engine when pulling over in a rest area for sleep to prevent carbon monoxide poisoning and maintain a peaceful environment for others.
Step-by-step explanation:
When you pull over in a rest area for sleep, it is important to turn off your engine because sleeping with the engine running can lead to the buildup of carbon monoxide (CO) gas inside the vehicle. CO gas is odorless, colorless, and can be deadly if inhaled in high concentrations. Turning off the engine helps prevent CO poisoning and ensures a safe sleeping environment.
Additionally, leaving the engine running can cause unnecessary noise and disturb other people who are trying to rest in the rest area.