IACR Process

UDOT Interchange Access Change Request Process

1 INTRODUCTION

This Memorandum documents the process generally required by FHWA for UDOT to request changes to the Interstate System. The interstate system serves a broader purpose to connect states across America. In order to protect that interest, FHWA maintains jurisdiction over the interstates. The United States Code (USC) includes legal rights and requirements regarding the traffic safety and operations of the interstate system. Those requirements are further detailed in the FHWA IACR Guidance Document. UDOT partners with FHWA’s local Utah office to refine these requirements based on UDOT’s data rich system. This allows UDOT to use data analytics that we have invested in to streamline the process and produce more accurate analyses.

2 UDOT TRAFFIC DATA

UDOT has invested in traffic safety and operations data and analytics to drive more objective data-driven decisions. This data has been integrated into processes from the very beginning when projects are prioritized and scoped all the way through construction. Primary data sources used in the IACR process include the anonymous probe traffic data available statewide through Iteris Clearguide and the anonymous 2,270 point traffic data stations collected through side-fire radar. UDOT is investigating data collected via video and lidar but currently side-fire radar is the only data detection that has been approved for use in this process. Data collected from ATSPMS are generally appropriate for high-level analyses, but they do not currently meet accuracy requirements for IACRs.

3 IS AN IACR REQUIRED?

An IACR is specifically required for changes to the access of the interstate system. This is because these kinds of changes can have an impact on the safety and operations of the interstate. Freeway projects that do not connect to Interstates (example: SR-201, Bangerter Highway, Mountain View Corridor) do not go through the FHWA IACR process. Rather, these projects are reviewed by the UDOT Region, Central UDOT Traffic & Safety (Safety) and the UDOT Traffic Management Division (TMD).

Projects that impact Interstates but do not impact access points (interchanges and gated entries), do not go through the federal process either. For example, adding a climbing lane or widening a shoulder on a bridge, whose scope does not impact any interchanges, ramps, ramp termini, or gores, will not need to go through the FHWA process. Rather, these projects are reviewed by the Region and by Safety and the TMD.

Projects that may impact a ramp terminus such as an additional left turn storage bay, or an auxiliary lane addition between gore points, will require FHWA approval but will typically be approved by FHWA to go through the more streamlined OSA process (Operations and Safety Assessment). FHWA approvals for an OSA level (rather than an IACR) are done at the scoping phase of the project. UDOT Safety and TMD review and approval is required before an IACR can be submitted to FHWA for review.

Projects that impact ramp configurations and interchange types require the full IACR process. Safety and the TMD are responsible for reviewing the IACR at several stages of the process to make sure standards are met and projects are built to operate safely and effectively. UDOT Safety and TMD reviews and approvals are required before an IACR can be submitted to FHWA for review.

Projects that propose partial interchanges will be escalated above the Utah local FHWA office for approval. Note that this will substantially impact a project’s schedule and needs to be planned accordingly. Generally, UDOT does not support partial interchanges either. There are safety and operational benefits to having complete interchanges. This is even the case when a particular ramp movement may not have substantial demand to immediately require it. In these cases, UDOT will typically phase the project and identify specific trigger points in the IACR, such as the completion of a development or arterial widening, to implement the final phasing of the project.

Note that the Department’s Maintenance of Traffic (MOT) program often uses neighboring interchanges to facilitate mobility during maintenance and construction of the system. SPUIs are used as effective U-turns in a diversion and Diamonds are used to effectively ramp-surf traffic in capacity-constrained locations. The resiliency in the system also becomes important when dealing with major events like crashes and weather impacts. Partial interchanges do not contribute to that resiliency near as much as full interchanges do.

4 THE OSA PROCESS

The following steps outline the OSA process for projects that qualify for the streamlined analyses.

4.1 Scoping and Approval for an OSA to be conducted

The UDOT Project Manager (PM) will usually reach out to the TMD for an evaluation of the project scope. This includes a general discussion of the purpose of the project, the schedule, the goals and potential area of influence. The TMD is responsible for guiding the project towards either an OSA, an IACR or solutions that do not require the FHWA process.

Sometimes the UDOT PM has already contracted a Consultant as part of the environmental process to handle the IACR in anticipation that an IACR is needed. Other times, the UDOT PM is looking for guidance as to which process will be necessary before bringing a Consultant on board. The TMD is responsible for providing guidance to the PM for their specific project as requested.

4.2 FHWA Preview Meeting 1

Once the TMD identifies the most likely outcome, and the UDOT PM has a Consultant under contract, the Consultant will set up a meeting with the TMD and FHWA to review the request for the selected process. The TMD currently has the most amount of experience in these processes, therefore, we fill the role of both liaison between projects and FHWA and as traffic operation engineers. This role could change with future personnel.

4.3 Existing & Future Models

If FHWA approves the project for an OSA, the Consultant will enter the request for the OSA review into the UDOT IACR Tracker and mark it as an OSA through the UDOT Operations Form. That single request will remain active through the OSA process.

The TMD is responsible for setting the project up in the FHWA Form, the Operations Form and the Safety Form. The TMD is also responsible for setting up the Consultant Representative with access to the UDOT Operations Google Drive where all of the IACR and OSA documents reside. (Although most of the Consultant Representatives have been granted access already through past projects). The TMD will then work directly with the Consultant on the development of the model constraints, the evaluation of the existing VISSIM models, the evaluation of forecasted volumes, the evaluation of the future VISSIM models and the evaluation of the final report. These are normally done in project update meetings between the Consultant and the TMD to limit unnecessary paperwork.. However, the TMD updates each project review with notes every week in case a PM wants to monitor progress more closely.

4.4 OSA Report

Once the Safety Study is completed, the results are compiled in the OSA. At this point the Consultant submits a single review request for the OSA through the UDOT Safety Form. Safety works directly with the Consultant to address comments and will mark it as approved in the UDOT IACR Tracker.

Likewise, the TMD will mark the project as approved in the UDOT IACR Tracker once our comments have been addressed. If comments are minor, then conditional approval will be granted with the agreement that final minor comments will be addressed. This prevents unnecessary bottlenecks in the schedule.

4.5 FHWA Preview Meeting 2

At this point the Consultant will set up a meeting with the TMD, Safety and FHWA to preview the results of the OSA. After that discussion, the Consultant will submit the OSA to FHWA for review and approval through the FHWA Form.

Once FHWA approves the OSA, FHWA will send a formal email confirming approval, and they will mark the OSA as approved in the UDOT IACR Tracker.

5 THE IACR PROCESS

The following steps outline the IACR process for projects that require a more comprehensive analysis.

5.1 Scoping

The UDOT Project Manager will usually reach out to the TMD for an evaluation of the project scope. This includes a general discussion of the purpose of the project, the schedule, the goals and potential scope. The TMD is responsible for guiding the project towards either an OSA, an IACR or solutions that do not require the FHWA process.

5.2 FHWA Preview Meeting 1

Once the TMD identifies the most likely outcome, the Consultant will set up a meeting with the TMD, FHWA and Safety to review the request for the selected process. The Consultant should come prepared with a map of the area of influence and the extended traffic operations scope (which is common for UDOT projects). The Consultant will lead the discussion, going over the project purpose and need, proposed alternatives and potential phasing. FHWA will confirm an IACR is needed during this meeting.

5.3 Methods & Assumptions

Once FHWA confirms that an IACR is needed, the Consultant will enter the project into the UDOT IACR Tracker by submitting a Scope Review Request through the UDOT Operations Form.

The Consultant will draft the Methods & Assumptions using UDOT’s M&A Template. The Consultant submits the M&A to the TMD for review through the UDOT Operations Form and to Safety for review through the UDOT Safety Form. The TMD and Safety will work directly with the Consultant to address any comments. The TMD and Safety will mark the M&A as approved in the UDOT IACR Tracker. Then the Consultant submits the M&A to FHWA for review through the FHWA Form.

5.4 Existing Models

Often the Consultant will begin work on the existing models immediately while the M&A is being reviewed. This helps streamline the process and works well if the FHWA preview meeting is done beforehand. The Consultant submits the Existing Models to the TMD for review through the UDOT Operations Form. The TMD works directly with the Consultant to address any comments in the model and will mark the Existing Models as approved in the UDOT IACR Tracker.

5.5 Future Models

Often the Consultant will also submit the Future Models alongside the Existing Models but not always. Sometimes the Existing and Future Models are submitted together. Either way, the TMD works directly with the Consultant to address any comments in the models. The TMD is responsible for ensuring that Modeling Guidelines are met and Signal Standards and the field signal operations are appropriately coded in the models. Both the Consultant and the TMD are responsible for ensuring that the models reflect the design. This is one reason why the signing and striping is included in the IACR. Safety, however, is the primary review authority for the signing and striping plan. The TMD will mark the Future Models as approved in the UDOT IACR Tracker.

5.6 Model PS&E 

The Model PS&E follows the same format as a Design PS&E.  Just as in design, there are so many components to reviewing a model that it is more efficient to do this as a group.  A Model PS&E also ensures clear communication and consistency between the traffic model and the design.  The Project modeler is responsible for scheduling the Model PS&E which includes UDOT TMD, UDOT Safety, and the Project designer to review traffic operations and safety specific “plans, specifications and estimates”.  

The acronym PS&E has been adopted for this because it reflects the level of completion in regards to a traffic analysis.  “Plans” refer to the signing & striping plans for safety and the area of influence inside the model.  “Specifications” refer to requirements outlined in the Traffic Analysis Guideline and the UDOT Safety Standards and Guidelines.  “Estimates” refer to the MOEs being reported.  

In order to simplify results that need to be documented inside the IACR, MOEs reported will focus only on the intersections inside the Area of Influence.  For all other intersections included in the scope of the project, the Project modeler will load the UDOT standard .layx files to facilitate presentation and review.  

Once UDOT TMD and UDOT Safety signs off on the Model PS&E, UDOT will issue a signed letter that is included in the Draft IACR.  This letter is meant to simplify the description of the detailed work that went into the review and document that the model has been thoroughly reviewed, that it meets the UDOT Traffic Analysis Guidelines, that it meets UDOT Safety Standards & Guidelines, that it meets the requirements agreed upon with FHWA in the Methods & Assumptions, and that it has been approved by UDOT for submittal to FHWA.

5.7 Draft IACR - UDOT

The Consultant submits the Draft IACR for review through the UDOT Operations Form and the UDOT Safety Form for review. The TMD and Safety will work directly with the Consultant to address any comments. Once approved, the Consultant can schedule the FHWA Preview Meeting 2.

5.8 FHWA Preview Meeting 2

The Consultant schedules a meeting with FHWA to preview the results of the Draft IACR once the models have been approved and either the Draft IACR has been approved by UDOT TMD and Safety, or it has reached near-completion. This allows the schedule to move forward as quickly as possible. The TMD leads the discussion to make sure specific questions are answered and FHWA’s concerns are addressed. The Consultant presents the project, going over the Build and No Build Alternatives and any phasing that has been proposed. The Consultant should come prepared with the actual Build models, volume counts, design layout, sign layouts, and details such as ramp lengths, interchange spacing, weave and merge distances. The Consultant should plan to discuss the results of the Build and No Build Alternatives and come prepared with maps showing all intersection LOS and freeway speeds and link LOS (based on densities). For large projects, this preview may take multiple meetings to get through.

Normally, the Consultant submits the Draft IACR for review and approval to the TMD and to Safety through the UDOT IACR Tracker before the FHWA preview. However, these steps can be interchangeable if the Draft IACR is far enough along to have a productive discussion.

5.9 Draft IACR

Once FHWA feels comfortable with the proposed Build scenario that is being recommended, the Consultant submits the Draft IACR to FHWA for review through the FHWA Form. Sometimes the FHWA preview meeting is done while the Draft IACR is still underway in order to squeeze some efficiencies out of the schedule. Either way, the Draft IACR needs to be approved by the TMD and Safety before it can be submitted to FHWA for approval. FHWA has limited resources so it is important to avoid sending documents that are unfinished as that only creates confusion and slows the process down.

5.95 Final IACR

FHWA will work directly with the Consultant to address comments on the Draft IACR. Once the Area Engineer approves the Draft IACR, the Consultant submits the Final IACR through the UDOT IACR Tracker. At this stage, FHWA will work process the Final IACR internally for final reviews and will send a formal approval to the Project Manager.