Here are a couple of cool maps showing flows of goods by truck to, from and within Washington state.  Flows include domestic and international freight moving by truck on highway segments with more than twenty-five trucks per day and between places typically more than fifty miles apart.

The first map, for 2007, is based on the economic census for that year:

The second map shows the forecast for 2040:

The data and forecasts shown come from the Federal Highway Administration’s Freight Analysis Framework. PDF’s of the maps can be found here.