That's part of it. Plus, I'd rather just chill out and let all those cars pass me with anywhere from 6 feet (if I'm sitting on a concrete bridge like I was yesterday) to 20 feet (if I'm sitting under a tree like I was a week or so ago), rather than have 30 cars pass me with mere inches to spare, one after another after another. A few minutes of delay by train, what's another 60 seconds to wait for traffic to thin down a bit?