What are Letters, Comments, and Statements?

Aii’s work does not end when research is published. As an independent infrastructure think tank, we engage in public-policy and regulatory discussions by submitting comments, communicating with policymakers and regulators, providing testimony and statements, and bringing relevant research and analysis into the public record. These engagements allow Aii to contribute independent evidence and perspective when important infrastructure questions are being considered.

The materials below provide a selected public archive of Aii-authored letters, regulatory comments, testimony, statements, and other formal communications. Other materials not found here may include private correspondence, letters of recommendation or support, grant-related letters, coalition sign-on letters, and other communications outside the scope of this archive.

Aii’s presence in the public record also extends well beyond the materials we author ourselves. Our research and analysis are regularly cited, quoted, referenced, and relied upon by others in regulatory filings, court documents and judicial opinions, amicus briefs, legislative materials, academic work, and other public records. We highlight a selection of those instances on our In the Media page, although many more are not catalogued.

CoverTitlePublishedKeywordsDownloadhf:doc_categorieshf:doc_tags
Aii Comments on America’s Great Corridors of Commerce (AGCC)
Aii Comments on America’s Great Corridors of Commerce (AGCC)October, 2026, , , , commentseconomics energy transmission damage-prevention transportation
Aii Letter of Support for the BUILD America 250 Act
Aii Letter of Support for the BUILD America 250 ActMay, 2026letterstransportation
Aii Comments on PHMSA Hazardous Materials Preemption Authority
Aii Comments on PHMSA Hazardous Materials Preemption AuthorityFebruary, 2026, commentsenergy transportation
Aii Comments on Revitalizing Washington Dulles International Airport
Aii Comments on Revitalizing Washington Dulles International AirportJanuary, 2026, , commentseconomics innovation-and-technology transportation
Aii Comments on PHMSA Regulatory Review and Damage Prevention Technology
Aii Comments on PHMSA Regulatory Review and Damage Prevention TechnologyJune, 2025, , commentspublic-safety energy damage-prevention
Aii Comments on FRA Waiver Reform and Rail Safety Innovation
Aii Comments on FRA Waiver Reform and Rail Safety InnovationMay, 2025, , commentsinnovation-and-technology rail transportation
Aii Submits Rail Safety and Regulatory Reform Research to USDOT
Aii Submits Rail Safety and Regulatory Reform Research to USDOTMay, 2025, , commentspublic-safety rail transportation
Aii Comments Supporting the Stibnite Gold Project
Aii Comments Supporting the Stibnite Gold ProjectJanuary, 2023commentseconomics
Aii Comments on FRA Train Crew Size and Rail Safety
Aii Comments on FRA Train Crew Size and Rail SafetyDecember, 2022, , commentspublic-safety rail transportation
Aii Supports the REST Act to Streamline Cross-Border Trade
Aii Supports the REST Act to Streamline Cross-Border TradeJune, 2020, statementseconomics transportation
Aii Testimony Supporting Enhanced Positive Response for Pipeline Damage Prevention
Aii Testimony Supporting Enhanced Positive Response for Pipeline Damage PreventionMay, 2019, , letterspublic-safety energy damage-prevention
Aii Recommends Updates to CGA Best Practices for Excavation Safety
Aii Recommends Updates to CGA Best Practices for Excavation SafetyApril, 2018lettersdamage-prevention
Aii Comments on DOT Regulatory Review Supporting Enhanced Positive Response
Aii Comments on DOT Regulatory Review Supporting Enhanced Positive ResponseOctober, 2017, , , commentspublic-safety innovation-and-technology energy damage-prevention
Aii Petitions PHMSA to Require Mandatory Excavation Damage Reporting in State Programs
Aii Petitions PHMSA to Require Mandatory Excavation Damage Reporting in State ProgramsMarch, 2017, , letterspublic-safety energy damage-prevention
Aii Petitions PHMSA to Require Mandatory Excavation Damage Reporting
Aii Petitions PHMSA to Require Mandatory Excavation Damage ReportingSeptember, 2016, , letterspublic-safety damage-prevention energy
Aii Comments on FRA Train Crew Staffing Requirements
Aii Comments on FRA Train Crew Staffing RequirementsJune, 2016, , commentspublic-safety rail transportation
Aii Urges Excavation Damage Focus in PHMSA Reauthorization
Aii Urges Excavation Damage Focus in PHMSA ReauthorizationSeptember, 2015, , letterspublic-safety energy damage-prevention
Aii Letter of Support for the Bridge to Sustainable Infrastructure Act
Aii Letter of Support for the Bridge to Sustainable Infrastructure ActApril, 2015, letterstransportation energy
Aii Supports Legislative Efforts to Improve the Highway Trust Fund
Aii Supports Legislative Efforts to Improve the Highway Trust FundApril, 2015letters
Aii Comments on the Crude-By-Rail Safety Act of 2015
Aii Comments on the Crude-By-Rail Safety Act of 2015March, 2015, , letterspublic-safety rail transportation

The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.

Our mission is to help foster innovative solutions to current and future infrastructure challenges. Our purpose is to support infrastructure issues providing greater awareness, influence, analysis, and assistance in formulating solutions to achieve improvements, advancements, and opportunities. We do this through nonpartisan coalitions and our the two nonprofits that form the Alliance.

Learn more About Us and Meet the Team today!