Travel time alert on Apple Watch

When I enter an event in Calendar, I often use the travel time feature. With few exceptions, I designate driving my car as the way to measure travel time. My watch is synced with my iPhone. Today, I have an appointment at 1 PM. My watch alerted me 3.5 hours in advance. I'm guessing because that would be how long it would take to get to my one o'clock appointment on foot from where I was at 9:30. I cannot see a way to make sure that the watch alerts are using the same mode of travel as the phone and computer.