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I have recently been looking into the various ways to compile travel distances and travel times.  As a school planner, I analyze the distances between subdivisions and schools.  This information is valuable when preparing school reassignment plans.  People are determined to attend the school which is closer and like to stretch the truth when they state their case for school assignment at public hearings.  I like to head off any misconception by providing this information ahead of time.

The process I usually use is with ArcGIS Network Analyst.  Travel distance has been my main focus in the past.  Just recently, some parents brought up the issue of actual travel time.  Although the distance may be shorter, the travel time was longer.  This point is valid and I determined to find a way to properly calculate this data point.

Network Analyst does allow for calculating travel time and distance; however, the base data that you use is the key factor.  My road data does not have the network attributes require to calculate travel time.  This becomes a factor with analyzing urban areas where the shortest route may not necessarily be the fastest.  A route may be the shortest because it cuts through a downtown grid; but red lights, speed limits, and one way streets are not considered.

So as a solution to this problem, I relied upon Google Maps (I also know that I can use ESRI’s online service StreetMap).  Entering each route individually until all data (time and distance) was calculated.  Right now, this works fine; however, analyzing the entire county may become a problem as individual analysis would be very time consuming.

As a conclusion to the travel distance and time problem, I will continue to reasearch this issue.  Since I analyze at a local area, this isn’t too much of an issue but I am always looking for ways to refine my processes.  I have posted a little bit of this issue on The GIS Form.