I have a line feature class representing road segments, with each road segment having a unique ID. This feature class has an attribute of average observed daily traffic counts. I have another table which contains more information about each road segment, but each road segment ID in the table has 8 entries (each of which corresponds to a 3-hour period).
I've set up a Relate between the feature class and the table, and have added a new field to the feature class that I would like to populate with the sum of 8 values from the table that share the same road segment ID (i.e. one attribute, represented by 8 measurements from different times-of-day).
I'd like to do this using the Field Calculator or Model Builder. Python would be preferred over VBScript.