Design

Interstate System Access

Superseded on 5/22/17 by Interstate Access Policy

Formerly Federal-Aid Policy Guide Non-Regulatory Supplement NS 23 CFR 630C
June 17, 1998
See Order 1321.1C FHWA Directives Management

This document includes information on additional access to the interstate system, temporary closure of interstate highways, and locked gate access points on interstate highways that was formerly included in FHWA Federal Policy Guide Supplement NS 23 CFR 630C

1. Additional Access to the Interstate System
   1. Policy. It is in the national interest to maintain the Interstate System to provide the highest level of service in terms of safety and mobility. Adequate control of access is critical to providing such service. Therefore, new or revised access points to the existing Interstate System should meet the following requirements:
      1. The existing interchanges and/or local roads and streets in the corridor can neither provide the necessary access nor be improved to satisfactorily accommodate the design-year traffic demands while at the same time providing the access intended by the proposal.
      2. All reasonable alternatives for design options, location and transportation system management type improvements (such as ramp metering, mass transit, and HOV facilities) have been assessed and provided for if currently justified, or provisions are included for accommodating such facilities if a future need is identified.
      3. The proposed access point does not have a significant adverse impact on the safety and operation of the Interstate facility based on an analysis of current and future traffic. The operational analysis for existing conditions shall, particularly in urbanized areas, include an analysis of sections of Interstate to and including at least the first adjacent existing or proposed interchange on either side. Crossroads and other roads and streets shall be included in the analysis to the extent necessary to assure their ability to collect and distribute traffic to and from the interchange with new or revised access points.
      4. The proposed access connects to a public road only and will provide for all traffic movements. Less than "full interchanges" for special purpose access for transit vehicles, for HOV's, or into park and ride lots may be considered on a case-by-case basis. The proposed access will be designed to meet or exceed current standards for Federal-aid projects on the Interstate System.
      5. The proposal considers and is consistent with local and regional land use and transportation plans. Prior to final approval, all requests for new or revised access must be consistent with the metropolitan and/or statewide transportation plan, as appropriate, the applicable provisions of 23 CFR part 450 and the transportation conformity requirements of 40 CFR parts 51 and 93.
      6. In areas where the potential exists for future multiple interchange additions, all requests for new or revised access are supported by a comprehensive Interstate network study with recommendations that address all proposed and desired access within the context of a long-term plan.
      7. The request for a new or revised access generated by new or expanded development demonstrates appropriate coordination between the development and related or otherwise required transportation system improvements.
      8. The request for new or revised access contains information relative to the planning requirements and the status of the environmental processing of the proposal.
   2. Application
      1. This policy is applicable to new or revised access points to existing Interstate facilities regardless of the funding of the original construction or regardless of the funding for the new access points. This includes routes incorporated into the Interstate System under the provisions of 23 U.S.C. 139(a) or other legislation. Routes approved as a future part of the Interstate system under 23 U.S.C. 139(b) represent a special case because they are not yet a part of the Interstate system and the policy contained herein does not apply. However, since the intention to add the route to the Interstate system has been formalized by agreement, any proposed access points, regardless of funding, must be coordinated with the FHWA Division Office.
      2. This policy is not applicable to toll roads incorporated into the Interstate System, except for segments where Federal funds have been expended, or where the toll road section has been added to the Interstate System under the provisions of 23 U.S.C. 139(a).
      3. For the purpose of applying this policy, each entrance or exit point, including "locked gate" access, to the mainline is considered to be an access point. For example, a diamond interchange configuration has four access points. Generally, revised access is considered to be a change in the interchange configuration even though the number of actual points of access may not change. For example, replacing one of the direct ramps of a diamond interchange with a loop, or changing a cloverleaf interchange into a fully directional interchange would be considered revised access for the purpose of applying this policy.
      4. All requests for new or revised access points on completed Interstate highways must be closely coordinated with the planning and environmental processes. The FHWA approval constitutes a Federal action, and as such, requires that the National Environmental Policy Act (NEPA) procedures are followed. The NEPA procedures will be accomplished as part of the normal project development process and as a condition of the access approval. This means the final approval of access cannot precede the completion of the NEPA process. To offer maximum flexibility, however, any proposed access points can be submitted in accordance with the delegation of authority for a determination of engineering and operational acceptability prior to completion of the NEPA process. In this manner, the State highway agency can determine if a proposal is acceptable for inclusion as an alternative in the environmental process. This policy in no way alters the current NEPA implementing procedures as contained in 23 CFR part 771.
      5. Although the justification and documentation procedures described in this policy can be applied to access requests for non-Interstate freeways or other access controlled highways, they are not required. However, applicable Federal rules and regulations, including NEPA procedures, must be followed.
   3. Implementation. The FHWA Division Office will ensure that all requests for new or revised access submitted by the State highway agency for FHWA consideration contain sufficient information to allow the FHWA to independently evaluate the request and ensure that all pertinent factors and alternatives have been appropriately considered. The extent and format of the required justification and documentation should be developed jointly by the State highway agency and the FHWA to accommodate the operations of both agencies, and should also be consistent with the complexity and expected impact of the proposals. For example, information in support of isolated rural interchanges may not need to be as extensive as for a complex or potentially controversial interchange in an urban area. No specific documentation format or content is prescribed by this policy.
2. Closures or Partial Blockages of Interstate Highways
   1. It is FHWA's policy and responsibility to assure that the national system of Interstate highways is operated and maintained in a manner that will enhance safety and minimize disruptions to road use. The primary purpose of the Interstate System is to provide safety and efficient transportation for the movement of persons and goods. Proposals to use Interstate highways for special events which will disrupt the flow of traffic or endanger the safety of the public should be vigorously discouraged.
   2. The States are solely responsible for controlling all activities which take place on their highways. However, when a regional or division office becomes aware of a proposed event involving their region or State which they consider inconsistent with this policy, that office should advise the highway agency of the FHWA's specific safety concerns with the particular event.
   3. If the State does approve such events, the closure or disruption should be minimized, a reasonable alternate route should be provided, full consideration for the safe operation of detours and connecting facilities must be assured and all elements of the Interstate facility must be restored to their pre-existing conditions.
3. Additional Access Points to Existing Full Access-Controlled Interchange Ramps
   1. Local connections within interchanges -- especially on freeway-to-freeway ramps -- violate driver expectancy and introduce additional decision points in an area where the information processing task is already complex. They also create a high potential for traffic queuing back onto the through freeway lanes. In addition, such ramps seldom provide for full directional service, thus creating the possibility of wrong-way movements by drivers who wish to return or continue in the same direction.
   2. It is poor public policy as well as poor engineering practice to allow additional access to existing freeway ramps. In many cases, the additional access ramps would provide traffic service to individual developments. Interchanges on the Interstate System and normally on other freeways are designed to provide access to local areas -- not to individual developments or parcels. Ramps to and from freeways should connect to local area road networks which in turn perform the function of land service to individual generators.
4. Locked Gate Access Points on the Interstate System
   1. Locked gate access points on the Interstate system are used primarily to provide access for fire, medical and other emergency vehicles to reduce travel time, for maintenance activities at remote utility facilities and as part of the right-of-way consideration, to provide land access in remote locations.
   2. Any request for locked gate access should be reviewed to ensure that vehicles can enter the Interstate safely, appropriate sight distance is available to and from the access, and the access is located such that the intended function is served (distance to nearest interchange and/or median crossover). Each new locked gate access approval needs to incorporate the following conditions:
      1. The gate shall be locked at all times except when opened for passage of the authorized vehicles. The distribution of keys for the lock should be limited.
      2. The access roadway will be constructed of any inconspicuous natural material to discourage unauthorized use.
      3. The purpose of the access should be specified.