the ports-to-plains corridor, also known as national highway system high priority corridor 38, is a highway corridor between the united states mexico border at laredo, texas and denver, colorado. it is the southern third of the ports-to-plains alliance. the reason for proposed improvements to this corridor is to expedite the transportation of goods and services from mexico in the united states and vice versa. the ports-to-plains corridor starts in south texas and traverses through texas, new mexico, oklahoma, and ends in denver, colorado.