Section 103(b), of title 23, U.S.C., allows the States to propose modifications to the National Highway System (NHS) and authorizes the Secretary to approve such modifications provided that they meet the criteria established for the NHS and enhance the characteristics of the NHS. In proposing modifications under 23 U.S.C. 103(b), the States must cooperate with local and regional officials. In urbanized areas, the local officials must act through the metropolitan planning organization (MPO) designated for such areas under 23 U.S.C. 134. The following guidance criteria should be used by the States to develop proposed modifications to the NHS.

1. Proposed additions to the NHS should be included in either an adopted State or metropolitan transportation plan or program.

2. Proposed additions should connect at each end with other routes on the NHS or serve a major traffic generator.

3. Proposals should be developed in consultation with local and regional officials.

4. Proposals to add routes to the NHS should include information on the type of traffic served (i.e., percent of trucks, average trip length, local, commuter, interregional, interstate) by the route, the population centers or major traffic generators served by the route, and how this service compares with existing NHS routes.

5. Proposals should include information on existing and anticipated needs and any planned improvements to the route.

6. Proposals should include information concerning the possible effects of adding or deleting a route to or from the NHS might have on other existing NHS routes that are in close proximity.

7. Proposals to add routes to the NHS should include an assessment of whether modifications (adjustments or deletions) to existing NHS routes, which provide similar service, may be appropriate.

8. Proposed modifications that might affect adjoining States should be developed in cooperation with those States.

9. Proposed modifications consisting of connections to major intermodal facilities should be developed using the criteria set forth below. These criteria were used for identifying initial NHS connections to major intermodal terminals. The primary criteria are based on annual passenger volumes, annual freight volumes, or daily vehicular traffic on one or more principal routes that serve the intermodal facility. The secondary criteria include factors which underscore the importance of an intermodal facility within a specific State.

Primary Criteria Commercial Aviation Airports

1. Passengers—scheduled commercial service with more than 250,000 annual enplanements.

2. Cargo—100 trucks per day in each direction on the principal connecting route, or 100,000 tons per year arriving or departing by highway mode.

Ports

1. Terminals that handle more than 50,000 TEUs (a volumetric measure of containerized cargo which stands for twenty-foot equivalent units) per year, or other units measured that would convert to more than 100 trucks per day in each direction. (Trucks are defined as large single-unit trucks or combination vehicles handling freight.)

2. Bulk commodity terminals that handle more than 500,000 tons per year by highway or 100 trucks per day in each direction on the principal connecting route. (If no individual terminal handles this amount of freight, but a cluster of terminals in close proximity to each other does, then the cluster of terminals could be considered in meeting the criteria. In such cases, the connecting route might terminate at a point where the traffic to several terminals begins to separate.)

3. Passengers—terminals that handle more than 250,000 passengers per year or 1,000 passengers per day for at least 90 days during the year.

Truck/Rail

1. 50,000 TEUs per year, or 100 trucks per day, in each direction on the principal connecting route, or other units measured that would convert to more than 100 trucks per day in each direction. (Trucks are defined as large single-unit trucks or combination vehicles carrying freight.)

Pipelines

1. 100 trucks per day in each direction on the principal connecting route.

Amtrak

1. 100,000 passengers per year (entrainments and detrainments). Joint Amtrak, intercity bus and public transit terminals should be considered based on the combined passenger volumes. Likewise, two or more separate facilities in close proximity should be considered based on combined passenger volumes.

Intercity Bus

1. 100,000 passengers per year (boardings and deboardings).

Public Transit

1. Stations with park and ride lots with more than 500 vehicle parking spaces, or 5,000 daily bus or rail passengers, with significant highway access (i.e., a high percentage of the passengers arrive by cars and buses using a route that connects to another NHS route), or a major hub terminal that provides for the transfer of passengers among several bus routes. (These hubs should have a significant number of buses using a principal route connecting with the NHS.)

Ferries

1. Interstate/international—1,000 passengers per day for at least 90 days during the year. (A ferry which connects two terminals within the same metropolitan area should be considered as local, not interstate.)

2. Local—see public transit criteria above.

Secondary Criteria

Any of the following criteria could be used to justify an NHS connection to an intermodal terminal where there is a significant highway interface:

1. Intermodal terminals that handle more than 20 percent of passenger or freight volumes by mode within a State;

2. Intermodal terminals identified either in the Intermodal Management System or the State and metropolitan transportation plans as a major facility;

3. Significant investment in, or expansion of, an intermodal terminal; or

4. Connecting routes targeted by the State, MPO, or others for investment to address an existing, or anticipated, deficiency as a result of increased traffic.

Proximate Connections

Intermodal terminals, identified under the secondary criteria noted above, may not have sufficient highway traffic volumes to justify an NHS connection to the terminal. States and MPOs should fully consider whether a direct connection should be identified for such terminals, or whether being in the proximity (2 to 3 miles) of an NHS route is sufficient.