Hi David
Have you looked at the SMP help doc in the Routing section? Open the help.htm file that's in the \documentation folder on DVD1. The historic traffic data is built into the network dataset, so it's not like a table that you look at or a feature class. The paragraph about historic traffic says this:
The historical traffic data can only be accessed with ArcGIS 10.1 SP1 or later. Using the historical traffic data will result in more accurate travel times, as the data stores traffic flow information by day of the week and time of day. For example, routing through the city at 7:30 am on a weekday will take longer than routing through the city at midnight. The traffic data can be utilized by specifying start times when creating routes using the Find Route tool or the Network Analyst extension. You can also display the traffic data by using the Time Slider tool. There is a new AvgTrafficTime impedance which can be used for routing. Using AvgTrafficTime, with or without specifying a start time, will use average speed values previously calculated from the historic traffic data. This will result in quicker performance than when selecting the TrafficTime impedance, which uses the actual historic traffic data based on time of day.
Hope this helps.
