For each county in your selected region(s), TREDIS provides a series of supplementary maps that show transportation market access areas. This includes: 

1. 40-minute labor market access area, and
2. Same-day truck delivery area.

These areas are determined using Geographic Information System (GIS) technology from ESRI, to measure and portray the areas that can be accessed within typical commuting travel times and same-day truck delivery times. The market areas are based on the population-weighted center for each county. They extend outward on the basis of existing roadway networks and average speeds for each road link in the network. The GIS system is then used, along with updated estimates of census data, to calculate total population and total employment characteristics of those access areas.

A typical map is shown here. It displays the area reachable within 40 minutes from the population center of the county. Other TREDIS reports also provide population and employment characteristics for this area.