Description of Figure 7. Freight Economics Influence Diagram

This schematic diagram shows the influence effects of highway improvement projects on infrastructure and infostructure factors.

The diagram begins in the upper left with Highway Investments. A down arrow indicates a positive effect on Highway Improvement Projects. Below Highway Improvement Projects and in the middle at the left of the diagram, a down arrow points to Transport Infrastructure Attributes, which is followed by a list of four attributes: Flow Capacity, Height and Weight Restrictions, Port Access, and Safety.

A horizontal arrow to the right indicates a negative influence on Shipment Characteristics, which is followed by a list of five characteristics: Transportation Link, Weight, Mode, Travel Time, and Time Variability. A left-facing brace joins the bottom two characteristics, Travel Time and Time Variability. Two right pointing arrows come from Travel Time and Time Variability. An upward diagonal arrow points right to Direct Shipper Transportation Cost Savings. Two exit arrows come from Direct Shipper Transportation Cost. A down arrow indicating a positive effect leads to Logistics Cost Savings. Continuing on the upward diagonal path from Direct Shipper Transportation Cost Savings, an upward diagonal arrow points right and indicates a positive effect on Transport Demand. From there, a looped arrow returns back to the left to show an induced balancing effect on Shipment Characteristics.

Returning to the main horizontal line of influences and picking up with Logistics Cost Savings, a horizontal arrow to the right indicates a reduction and leads to Product Price. A horizontal arrow to the right indicating a decline leads to Product Demand. From Product Demand, a vertical upward arrow indicating a positive influence leads to Quantity Shipped and Total Sales. Two arrows exit Quantity Shipped and Total Sales. The left-pointing arrow links back to Transport Demand. The right-pointing arrow splits and indicates (1) a positive influence leading to Firm Productivity and (2) a positive influence on Revenues.

Following Revenues is a loop indicating a reversal of downhill slides. First in the loop is Increased Capital Investment. A left pointing arrow indicating a decrease from Positive Capital leads to Warehouses. From Warehouses, a vertical upward arrow indicating a positive influence leads to Inventory Stock, both Base and Safety margin. A right-facing brace links Warehouses and Inventory Stock with Logistics Reorganization. From Inventory Stock, an upward vertical arrow indicating a negative influence leads to Indirect Shipper Cost Savings. From Vertical Cost Savings, a vertical upward arrow indicating a positive influence closes the loop back at Logistics Cost Savings.