This Chapter discusses highway infrastructure improvements that may be required to mitigate the effects of site-generated traffic on the State highway road network and/or implement regional transportation facilities. These “off-site” highway improvements are typically identified in connection with the land development approval process, to address traffic and safety issues on State highways and adjoining public roads. Improvements range from minor intersection geometric adjustments and traffic signal modifications to extensive, complex highway improvement projects. The magnitude of improvements required for a given development project depends on the traffic impacts generated by the development, the ability of the existing road network to handle the impacts, and the framework for development approval established by the local government approving authority.

14.1 Identification of Improvements Required

14.1.1 Basis.

State highway improvements, apart from those required for site access as discussed in Chapter 13, may be identified by SHA, the local jurisdiction, or both in connection with the development approval process. SHA is a concurrent reviewing agency in most local subdivision and development review processes. SHA’s recommendations concerning highway improvements are based on, but not limited to, the following considerations:

  • Findings of the approved Traffic Impact Study
  • Safety and traffic operational concerns, whether exhibited or potential, recognized by SHA
  • Improvements required to ensure compatibility between proposed site access and programmed State highway improvements
  • Coordination to ensure compatibility between proposed development access and highway corridor access management objectives

14.1.2 Authority.

Implementation of highway infrastructure improvements recommended by SHA is typically required of the developer as a condition of development approval by the local approving authority, in accordance with Adequate Public Facilities Ordinances or project-specific resolutions. Off-site improvements are generally intended to maintain acceptable levels of service on the local and regional road network, including State highways, as required by local Adequate Public Facilities Ordinances. However, the State reserves the ability to require road improvements that are necessary to maintain and protect public safety, apart from the local process.

14.2 Feasibility of Improvements.

Highway improvements are often identified in general terms during the preliminary stages of project evaluation and traffic impact analysis. It is the developer's responsibility to confirm the feasibility of any highway improvements identified through the traffic impact study review and approval process. The developer should ensure that all design requirements, site constraints, utility relocations, property impacts, and environmental issues associated with the identified improvements are thoroughly evaluated before conditions of development approval are imposed by the local approving authority. Cost sharing arrangements, phasing of improvements, and appropriate community input should also be considered at this stage. In the event that the approved improvements are not feasible, alternate improvements may be required of the developer to produce equivalent mitigation of safety and/or traffic issues.

14.3 Implementation.

All State highway infrastructure improvements shall conform to SHA requirements and be constructed under an Access Permit. As with any permitted project, the developer is responsible for obtaining all necessary right-of-way, permits, and approvals.

14.3.1 Design.

SHA review and approval of infrastructure improvement projects is handled as described in Chapter 7 for “Intermediate” or “Major” projects. Special requirements for the design of highway infrastructure improvements include the following:

  1. Geometric Design. The geometric layout of the improvements shall be designed to: (1) fulfill the objectives of the required traffic mitigation as identified in the approved Traffic Impact Study; and (2) meet the requirements for safe and appropriate highway design in accordance with AASHTO policy and SHA standards, specifications, and accepted engineering practices.
  2. Typical Sections of Improvement. The lane width and roadside design standards established in Chapter 15 shall be met. Widening shall be required to accommodate the proposed improvements unless acceptable lane widths, shoulders, and roadside conditions can be maintained within the existing pavement section. Bicycle and pedestrian compatibility guidelines shall apply to the design of all highway improvements.
  3. Turning Movements. Where an existing intersection is modified to accommodate additional turning movements, sufficient separation must be demonstrated between opposing movements for the appropriate design vehicle(s).
  4. Roundabouts. Roundabouts shall be designed to accommodate the full range of vehicles that may reasonably be anticipated at the location, following accepted geometric and traffic control design guidelines. Pertinent guidelines are presented in "Roundabouts: An Informational Guide", Publication #FHWA-RD-00-067. All roundabout designs must be approved by the SHA Office of Traffic and Safety.

14.3.2 Construction.

All improvements within State owned right-of-way on State highways require an Access Permit. This may be handled under the same permit as the requested site access or under a separate permit, at SHA's discretion. The local government, in coordination with SHA, will consider the anticipated implementation schedule for highway infrastructure improvements in connection with the anticipated build-out of the site and associated traffic volume projections.

14.3.3 Cost Sharing.

When the same highway infrastructure improvement is proposed to satisfy traffic mitigation requirements associated with more than one development project, it is the responsibility of the local jurisdiction, or others but not SHA, to determine the appropriate assignment of costs among the various developments, in accordance with local laws. Unless the improvement falls within the limits of an SHA project that is funded for construction in the Consolidated Transportation Program, SHA does not have the ability to collect and administer fees from various developers in lieu of the construction of improvements. In cases where extensive improvements are required to the State highway(s) by multiple developers, it is recommended that a "road club" be formed in partnership with the local jurisdiction to provide a mechanism to facilitate cost-sharing among the developers. In that case, either the local jurisdiction or a developer could implement construction of the improvements.