answer:Can the appointment be rescheduled for a time of day when traffic is more predictable? If this were my situation, I would probably try to arrange things so that I had somewhere else to go at the destination end, even if it was just a Starbuck’s with a free wifi, and allow more than the anticipated maximum time. So if it could take 3 hours, I’d probably plan on 3½. And then I’d do the other thing, sit in Starbuck’s or go shopping or visit someone or take a lunch to a park or whatever, until it’s time for the appointment. I’d also be asking if the thing I’m traveling for is something that could be done elsewhere, closer to home. If it’s just not that kind of thing at all—not an appointment, not something that can be scheduled to suit me—I’d make sure that everyone affected feels free to start without me.