I will demonstrate in a simple easy to understand concept (refer to link) :

I have a point (we'll call it Town A) with many different streets and street segments that are near it all with different street segment lengths (streets). The circular buffer I need to create is a particular size to contain streets and street segments that would total up to 300 miles of streets/segments which intersect or contain end points that intersect streets that are in the town centroid i.e. i take a truck and drive on all the streets that intersect the center of town A and my odometer should read 300 miles. If I use the buffer tool it will build a buffer that is 300 miles in diameter although a buffer that size would contain 1000s of miles of streets.

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I cannot see your link as it seems to require a username and login, but what I think you are describing is not really a buffer. It sounds instead like you are trying to determine is the area can be accessed by driving for a certain period of time. This is a question that can be answered using Network Analyst. Take a look at this link to see if the 3rd example illustrates your problem: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//004700000001000000. If it does, then continue reading about Network Analyst to find out about service area analysis: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Service_area_analysis/004700000048000000/.