Boiling water is water that's bubbling at 212ºF. ... Simmering, on the other hand, is slower than that nice bubbling boil. It's still very hot—195 to 211ºF—but the water in this state isn't moving as quickly and isn't producing as much steam from evaporation. Simmering water is great for soups, broths and stews.
Answer: They can help keep you from getting distracted while you're driving, they can act as a second eye to look for any potential dangers, and they can switch places with you if needed.
