While you are driving alone through the desert, your camper breaks down late in the afternoon, and you cannot fix it. You discover that the road you are traveling on is closed to traffic. There is no hope of anyone driving by to help you. There are no telephones nearby.
Your best solution is to walk back to a service station, which you remember passing. You calculate that you have driven about one hour and fifteen minutes at an average speed of 80-kilometers (50 miles) per hour. You will only be able to travel at night because of the intense heat and burning sun.