I'm trying to do a basic service area network analysis in ArcGIS 10.0. But I have two cost attributes I want to act as the network impedance-- one apportioned along the edges of each line feature, the other a constant.

To be specific, I'm trying to model transit travel. I have travel time (in minutes) as the primary cost attribute (which is apportioned along the line), but I also want to be able to factor in a constant wait time which is expended at the facility. The wait time will vary depending on the transit line's frequency.

Because the wait time varies from line to line, I can't just subtract the wait time from the default break values I put into the analysis settings. For instance, if I want to find out the extent of travel in 20 min and 30 min, and I had only one transit line (with a wait time of 5 min), I could just specify 15/25 as my break values. But I have multiple transit lines, so I can't specify break values for every line.

Is there any way around this?



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