Yes, the slope was very close to 65 across the board for interstate trips, so my hopes that somehow Mapquest knows about every traffic slowdown and wreck have been dashed. Hmm, I’m a member of AAA so I’m heading over there to see if their TripTik website does factor in other stuff (only to satisfy my own curiousity, not to integrate that into a lesson).

And thanks for that very Web 2.0ish hint about mousing over the flight details! I hadn’t even considered that so I just didn’t try….

I’d love to collect more real world applications of linear relationships that middle school or high school students can handle, like yours.

Re: Mapquest, so, I guess I could just find out for myself, but was the slope, like, 65 the whole way across? Were any routes noticeably above/below the line. eg. a trip that ran through Montana or straight along an interstate where the speed is 70 or 75.

Sounds more and more like a great precursor to the air travel activity, interpreting an insignificant and then a significant y-intercept.

I think that you’re right if we did trips within our own urban area, it would be a much more scattered plot. In reality, I’m starting to suspect that Mapquest just has some very linear function (with a y-intercept of zero) that calculates their estimated travel time. In other words, our best fit lines were mighty good because they really do fit on a straight line! BTW, how do you find the miles of each of your plane trips (I don’t think that the airline web pages show you that, do they?).