Thursday, May 01, 2008
Calculation Debates...driving edition
I was reminded on my drive to Chicago today of a fascinating road feature that always gets my mind stirring-- those road signs that tell you how long it is expected to take to get from where you currently are to a well-known place of interest. They are scattered throughout the Dan Ryan Expressway here, and they are used in the San Francisco Bay Area as well. What amazes me is how accurate they are.
Think of all of the variables that can affect how long it takes you to get from one place to the next-- and that they are constantly changing-- and to me, it's a small miracle that they are rarely more than a minute off one way or the other. I'm convinced this can't be the doing of any municipality; it's too useful and too effective. I bet communists love these things, too-- if we can calculate the complexities of rush hour traffic with great precision, surely an accurate Input/Output model is on the horizon, right?
Does anyone have any insight into the guts of these things? Is it any more than measuring the speed of passing cars at a few points along the road?