Not sure about where you are from, but in Canada distances are routinely given in hours or minutes, and it always means by car unless it is specified. As in, "Toronto to Ottawa is around five hours, or an hour by plane."
And that's the problem, tell me 10 miles and it will always be 10 miles. Where I live, in a rapidly growing city, 15 years ago it would take 15 minutes to downtown from my house, now it takes 25 or 30. It's the same distance but traffic has increased significantly in a short number of years.