Living in a populated area and the school being in one too can lead to a stressful situation. If time allows, it would be ideal to come in early to beat "rush hour" traffic for a morning or evening class. I have found this useful and even if the school isn't open in the morning, being in the area and getting breakfast can help calm the situation. Have you experienced commute stress? Have you set-up guidelines with your students in case you are late? If so, or if you don't but might do in the future, what are your guidelines?
