| NCHRP 25-02 | Predicting Stop-and-Go Traffic Noise Levels | Completed | |
| NCHRP 25-03 | Guidelines for the Development of Wetland Replacement Areas | Completed | |
| NCHRP 25-04 | Determining Economic Impacts on Adjacent Businesses Due to Restricting Left Turns | Completed | |
| NCHRP 25-05 | Remote Sensing and Other Technologies for the Identification and Classification of Wetlands | Completed | |
| NCHRP 25-06 | Intersection Air Quality Modeling | Completed | |
| NCHRP 25-07 | Improving Transportation Data for Mobile Source Emissions Estimates | Completed | |
| NCHRP 25-08 | Impact of Highway Capacity Improvements on Air Quality and Energy Consumption | Completed | |
| NCHRP 25-09 | Environmental Impact of Construction and Repair Materials on Surface and Ground Waters | Completed | |
| NCHRP 25-09(01) | Environmental Impact of Construction and Repair Materials on Surface and Ground Waters -- Outreach and Training | Completed | |
| NCHRP 25-10 | Estimating the Indirect Effects of Proposed Transportation Projects | Completed | |
| NCHRP 25-10(2) | Desk Reference for Estimating the Indirect Effects of Proposed Transportation Projects | Completed | |
| NCHRP 25-11 | Development of a Modal-Emissions Model | Completed | |
| NCHRP 25-12 | Wet Detention Pond Design for Highway Runoff Pollution Control | Completed | Report not published. |
| NCHRP 25-13 and 25-13(2) | Assessments of Impacts of Bridge Deck Runoff Contaminants on Receiving Waters | Completed | |
| NCHRP 25-14 | Heavy-Duty Vehicle Emissions | Completed | |
| NCHRP 25-15 | Short-Term Monitoring for Compliance with Air Quality Standards | Final | Completed and published as NCHRP Report 479 |
| NCHRP 25-16 | Guidance for Selecting Compensatory Wetland Mitigation Options | Completed | |
| NCHRP 25-17 | Transportation Effects of the 1997 Changes to the National Ambient Air Quality Standards | Final | Completed --- Agency report available on request |
| NCHRP 25-18 | Particulate-Matter (PM2.5 and PM10) Apportionment for On-Road Mobile Sources | Final | |
| NCHRP 25-19 | Evaluation of Methods, Tools, and Techniques to Assess the Social and Economic Effects of Transportation Projects | Completed | |
| NCHRP 25-20 | Management of Runoff from Surface Transportation Facilities--Synthesis and Research Plan | Completed | |
| NCHRP 25-20(01) | Evaluation of Best Management Practices for Highway Runoff Control | Completed | |
| NCHRP 25-20(02) | Identification of Research Needs Related to Highway Runoff Management | Completed | |
| NCHRP 25-21 | Predicting Short-Term and Long-Term Air Quality Effects of Traffic-Flow Improvement Projects | Final | |
| NCHRP 25-22 | Technologies to Improve Consideration of Environmental Concerns in Transportation Decisions | Completed | Report available as CRP-CD-14 |
| NCHRP 25-22(02) | Technologies to Improve Consideration of Environmental Concerns in Transportation Decisions | Final | |
| NCHRP 25-23 | Environmental Information Management and Decision Support System for Transportation | Completed | |
| NCHRP 25-23(2) | Software for an Environmental Information Management and Decision Support System | Completed | |
| NCHRP 25-24 | Monitoring, Analyzing, and Reporting on the Environmental Streamlining Pilot Projects | Final | |
| NCHRP 25-25 | Research for the AASHTO Committee on Environment and Sustainability | Final | |
| NCHRP 25-25/Task 001 | Synthesis on Data Needs for EA and EIS Documentation | Completed | |
| NCHRP 25-25/Task 002 | Transportation Impacts and 'Smart Growth' Initiatives | Completed | |
| NCHRP 25-25/Task 003 | Assessment and Mitigation Strategies for Land Development Impacts of Transportation Improvements | Completed | |
| NCHRP 25-25/Task 004 | Environmental Stewardship Practices, Policies, and Procedures for Road Construction and Maintenance | Completed | |
| NCHRP 25-25/Task 005 | Assessing the Current State of the NEPA Environmental Review Process | Completed | |
| NCHRP 25-25/Task 006 | Preparing State DOTs for Implementation of the 8-hour Ozone and PM2.5 Standards | Completed | |
| NCHRP 25-25/Task 007 | Evaluation of Mobile Models: MOBILE 6.1, MOBILE 6.2 and MOBILE6/CNG | Completed | |
| NCHRP 25-25/Task 008 | Developing Performance Data Collection Protocol for Stream Restoration | Completed | |
| NCHRP 25-25/Task 009 | Use of Existing Data in Decision Making | Completed | Cancelled |
| NCHRP 25-25/Task 010 | Alternative Mitigation Strategies/Early Mitigation: Streamlining and Achieving Net Benefits for the Natural Environment | Completed | |
| NCHRP 25-25/Task 011 | Secondary/Indirect and Cumulative Effects Analysis | Completed | |
| NCHRP 25-25/Task 012 | Design-Build Environmental Compliance Process and Level of Detail Required | Completed | |
| NCHRP 25-25/Task 013 | Agency Use and Approach to FHWA Approved Programmatic Agreements | Completed | |
| NCHRP 25-25/Task 014 | A Summary of Existing Research on Dam Removal Projects | Completed | |
| NCHRP 25-25/Task 015 | Historic Bridges | Completed | |
| NCHRP 25-25/Task 016 | State Transportation Agency Strategies to Address NPDES Phase II Requirements | Completed | |
| NCHRP 25-25/Task 017 | Assessment of Greenhouse Gas Analysis Techniques for Transportation Projects | Completed | |
| NCHRP 25-25/Task 018 | Recommended Approaches to Communicating Air Toxics Issues and Transportation Project-Related Analyses in NEPA Documents | Completed | |
| NCHRP 25-25/Task 019 | Historic Bridge Rehabilitation / Replacement Decision Making | Completed | |
| NCHRP 25-25/Task 020 | The Role of State DOTs in Support of Transit Oriented Development (TOD) | Completed | |
| NCHRP 25-25/Task 021 | Assessment of Geophysical Remote Sensing Opportunities at State Departments of Transportation for Incorporation into Archaeological Investigations | Completed | |
| NCHRP 25-25/Task 022 | Land Use Forecasting for Indirect Impacts Analysis | Completed | |
| NCHRP 25-25/Task 023 | Environmental performance measurements related to transportation project planning, design, construction, maintenance and operations | Completed | |
| NCHRP 25-25/Task 024 | Climate Change and U.S. Transportation | Completed | |
| NCHRP 25-25/Task 025 | Modification and Amendment of Environmental Permits on Design-Build Projects | Completed | |
| NCHRP 25-25/Task 026 | Integration of Charrette Processes into Project Planning | Final | Cancelled |
| NCHRP 25-25/Task 027 | Project Management and NEPA | Completed | Completed |
| NCHRP 25-25/Task 028 | Reevaluations of NEPA documents | Completed | |
| NCHRP 25-25/Task 029 | Best Practices Library from the Environmental Stewardship Practices in Construction and Maintenance Compendium | Completed | |
| NCHRP 25-25/Task 030 | Section 404 Permitting and Roadside Ditches as Jurisdictional Waters | Completed | Cancelled |
| NCHRP 25-25/Task 031 | Cost Effective Tools for Achieving PM 2.5 Transportation Air Quality Conformity | Completed | Cancelled |
| NCHRP 25-25/Task 032 | Linking Environmental Resource and Transportation Planning – The Current State of Practice | Final | This project is completed and results are available at the links below. |
| NCHRP 25-25/Task 033 | National Register of Historic Places Eligibility | Completed | |
| NCHRP 25-25/Task 034 | Streamlined Carbon Monoxide Hot Spot Screening / Modeling Tool | Completed | Cancelled |
| NCHRP 25-25/Task 035 | Water Quality Analyses for NEPA Documents: Selecting Appropriate Methodologies | Completed | Completed |
| NCHRP 25-25/Task 036 | Recurring Community Impacts | Final | The final report has been submitted to AASHTO |
| NCHRP 25-25/Task 037 | Effective Organizational Structures and Management Practices for Achieving Environmental Stewardship in Transportation Agencies | Final | Final Report sent to AASHTO. |
| NCHRP 25-25/Task 038 | Guide to Use of Tier I Environmental Impact Statements for Transportation Projects | Completed | The draft final report has been accepted and distributed to AASHTO. |
| NCHRP 25-25/Task 039 | Improving Project Environmental Cost Estimates | Final | The project is completed and the final report has been submitted to AASHTO. |
| NCHRP 25-25/Task 040 | New Noise Barrier Products & Noise Barrier Approval Research & Guidelines | Completed | Completed. |
| NCHRP 25-25/Task 041 | Implementation of Community & Cultural Resource Commitments | Final | This project is completed and the final report has been submitted to AASHTO. |
| NCHRP 25-25/Task 042 | Determine alternative calculations for fine particulate emission factors other than AP-42 applicable to calculate re-entrained dust on transportation projects | Final | The project has been completed and the final report submitted to AASHTO |
| NCHRP 25-25/Task 043 | Guidance on legal sufficiency criteria for adequate cumulative and secondary impacts analysis in EIS documents | Final | The project has been completed and the final report submitted to AASHTO |
| NCHRP 25-25/Task 044 | Development and Implementation of a Transportation and Climate Change Clearinghouse | Final | The clearinhouse has been completed and transferred to the U.S. DOT. |
| NCHRP 25-25/Task 045 | Transportation Program Responses to Greenhouse Gas (GHG) Reduction Initiatives and Energy Reduction Programs | Final | The project has been completed and the final report submitted to AASHTO |
| NCHRP 25-25/Task 046 | Compendium of Best Practices for Environmental Compliance and Stewardship at Transportation Maintenance Facilities | Final | The project has been completed and the final report submitted to AASHTO |
| NCHRP 25-25/Task 047 | Compendium of Best Practices for Incorporating Environmental Commitments into Transportation Project Construction Contract Documents | Final | The project has been completed and the final report submitted to AASHTO. |
| NCHRP 25-25/Task 048 | Compendium of Environmental Fieldwork Technologies | Final | The project has been completed and the final report submitted to AASHTO |
| NCHRP 25-25/Task 049 | Effective Practices for Considering Historic Preservation in Transportation Planning and Early Project Development | Final | Completed and final report sent to AASHTO SCOE. |
| NCHRP 25-25/Task 050 | Finding the Carrot Instead of the Stick - Incentive-based Approaches for Environmental Compliance | Final | The project has been completed and the final report submitted to AASHTO |
| NCHRP 25-25/Task 051 | Asset Management of Environmental Mitigation Features | Final | The project has been completed and the final report submitted to AASHTO. |
| NCHRP 25-25/Task 052 | Informational Requirements for Jurisdictional Determinations to be Issued by the Army Corps of Engineers (Corps) Under the Clean Water Act (CWA) | Final | The project has been completed and the final report submitted to AASHTO. |
| NCHRP 25-25/Task 053 | Stormwater Treatment with Vegetated Buffers | Final | The project has been completed and the final report submitted to AASHTO. |
| NCHRP 25-25/Task 054 | Evaluate Colorado's Area-wide Cumulative Effects Assessment (ACEA) Methodology as a Mechanism for Cumulative Impacts Analysis of Regional Transportation Plans | Final | The project has been completed and the final report submitted to AASHTO. |
| NCHRP 25-25/Task 055 | Design, Organize and Implement a Training Program for Mainstreaming Environmental Stewardship and Enhancement Activities into Planning and Project Development | Final | The project has been completed and the final report submitted to AASHTO. |
| NCHRP 25-25/Task 056 | Cost and Benefit of Transportation Specific MS4 and Construction Permitting | Final | Final report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 057 | Integrated State and Local Government Policy Approaches to Transportation and Climate | Final | Completed - Final Report sent to AASHTO |
| NCHRP 25-25/Task 058 | Methods to Address Greenhouse Gas Emissions from Transportation Construction/Maintenance/Operations Activities | Final | Completed and submitted to AASHTO SCOE |
| NCHRP 25-25/Task 059 | Evaluate the Interactions between Transportation-Related Particulate Matter, Ozone, Air Toxics, Climate Change, and Other Air Pollutant Control Strategies | Final | Final Report submitted to AASHTO SCOE. |
| NCHRP 25-25/Task 060 | Increased Use of Environmentally Preferable, Non-Toxic Products to Reduce Costs, Liabilities, and Pollution at DOT Offices, Maintenance Facilities and Rest Stops | Final | Final Report submitted to AASHTO. |
| NCHRP 25-25/Task 061 | Best Practices for Establishing and Maintaining Statewide Cultural Resource Databases at State DOTs | Final | Final Report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 062 | Improving the Effectiveness of Outreach to Traditional and Non-Traditional Groups by Integrating the Expertise of Existing and Emerging Citizen Coalitions into Transportation Analysis and Decision Making | Final | Final Report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 063 | Transportation Corridor Environmental Management Framework | Final | The project has been completed and the final report submitted to AASHTO |
| NCHRP 25-25/Task 064 | Feasibility Study of Using Solar or Wind Power for Transportation Infrastructure | Final | Completed. Final Report Submitted to AASHTO SCOE. |
| NCHRP 25-25/Task 065 | Synthesis of Greenhouse Gas Emission Inventory Methodologies for State Transportation Departments | Final | Completed. Final report submitted to AASHTO. |
| NCHRP 25-25/Task 066 | Best Practices and Lessons Learned on the Preservation and Rehabilitation of Historic Bridges | Completed | Final report delivered to AASHTO SCOE |
| NCHRP 25-25/Task 067 | Optimizing Conservation and Improving Mitigation Cost/Benefit | Final | Completed. Final Report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 068 | Implementing Measures to Reduce Highway Impacts on Habitat Fragmentation | Final | Completed and Final report submmited to AASHTO SCOE |
| NCHRP 25-25/Task 069 | Identification of Tools and Techniques to Define Community Context as Part of the Transportation Project Planning and Development Process | Completed | Final Report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 070 | Assessment of Quantitative Mobile Source Air Toxics in Environmental Documents | Completed | Completed and report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 071 | Templates for Project-Level Analyses Using MOVES and AERMOD | Completed | Completed and report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 072 | Current Practices to Address Construction Vibration and Potential Effects to Historic Buildings Adjacent to Transportation Projects | Completed | Completed and report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 073 | Improved Environmental Performance of Highway Maintenance | Completed | Completed and final report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 074 | Meeting the New EPA Effluent Limitations Guideline for Construction Site Discharge Turbidity: Effectiveness of Different Turbidity Control Systems and Monitoring Methods | Completed | Completed and submitted to AASHTO SCOE |
| NCHRP 25-25/Task 075 | Nationwide Evaluation of Transfer of Compensatory Wetland Creation Sites for Transportation Projects to Private Conservation Organizations or Government Conservation Agencies | Completed | Completed. Report Submitted to AASHTO SCOE |
| NCHRP 25-25/Task 076 | Synthesis of Climate Change and Transportation Research Efforts at State DOTs, State Universities, and the Federal Level | Final | Completed. Final Report submitted to AASHTO SCOE. |
| NCHRP 25-25/Task 077 | Strategic Options of Inventorying and Updating Environmental Guidance and Links | Completed | Completed and final report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 078 | Programmatic Agreements for Project-Level AirQuality Analyses Using MOVES, CAL3QHC/R and AERMOD | Completed | Completed--final deliverables available for AASHTO use |
| NCHRP 25-25/Task 079 | Successful Practices for Effective Tribal Consultation | Completed | Completed and report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 080 | Potential Use of Social Media Impact in the NEPA Process | Completed | Report completed and submitted to AASHTO SCOE |
| NCHRP 25-25/Task 081 | Federal Compliance for Projects Utilizing Alternative Funding Strategies | Completed | Completed and report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 082 | Permeable Shoulders with Stone Reservoirs | Completed | Completed and report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 083 | Current Practice of Post- Construction Structural Stormwater Control | Completed | Completed and final report submitted to AASHTO SCOE |
| NCHRP 25-25/Task 084 | Development of Construction Guidelines for Wildlife Fencing and Associated Escape and Lateral Access Control Measures | Completed | Final deliverable available for AASHTO use |
| NCHRP 25-25/Task 085 | Nutrient (Nitrogen/Phosphorous) Management and Source Control | Completed | Final deliverables available for AASHTO use |
| NCHRP 25-25/Task 086 | Toxicological Effects of Chloride Based Deicers in the Natural Environment | Completed | Completed |
| NCHRP 25-25/Task 087 | Coordination of Section 106 and Long Range Transportation Planning | Completed | Final deliverables available for AASHTO use |
| NCHRP 25-25/Task 088 | Giving Away the Bridge: A National Synthesis of on Transferring Ownership of Historic Bridges | Completed | Final deliverables available for AASHTO use |
| NCHRP 25-25/Task 089 | Establishing Representative Background Concentrations for Quantitative Hot-spot Analyses for Particulate Matter | Completed | Final deliverables available for AASHTO use |
| NCHRP 25-25/Task 090 | Application of Geographic Information Systems (GIS) for Historic Properties | Final | |
| NCHRP 25-25/Task 091 | Synthesis of Transportation Exclusions to Section 106 Review | Completed | Final deliverables available for AASHTO use |
| NCHRP 25-25/Task 092 | Transferability of Post-Construction Stormwater Quality BMP Effectiveness Studies | Completed | Completed--Final deliverables available for AASHTO use |
| NCHRP 25-25/Task 093 | Long-Term Construction and Maintenance Cost Comparison for Road Stream Crossing Hydraulic Design vs. Bankfull Width Design | Final | |
| NCHRP 25-25/Task 094 | Integrating Climate Change and Extreme Weather Into Transportation Asset Management Plans | Final | |
| NCHRP 25-25/Task 095 | SCOE Strategic Plan and Research Plan for SCOE Areas of Interest | Completed | Completed--Final deliverable available for AASHTO use |
| NCHRP 25-25/Task 096 | Quick Reference Guide for Traffic Modelers for Generating Traffic and Activity Data for Project-Level Air Quality Analyses | Final | |
| NCHRP 25-25/Task 097 | Historic Roads: A Synthesis of Identification and Evaluation Practices | Final | |
| NCHRP 25-25/Task 098 | Practical Guide for Developing Effective Scopes of Work for the Geophysical Investigation of Cemeteries | Final | |
| NCHRP 25-25/Task 099 | Lessons Learned from State DOT NEPA Assumption | Final | |
| NCHRP 25-25/Task 100 | Compilation of Existing Data on Northern Long-Eared and Other Cave-Dwelling Bat Habitat and the Roadside Environment | Final | Project cancelled |
| NCHRP 25-25/Task 101 | Stormwater Monitoring Program Goals, Objectives and Protocols for State Departments of Transportation | Final | |
| NCHRP 25-25/Task 102 | Artificial Bat Roost Mitigation Designs and Standardized Monitoring Criteria | Final | |
| NCHRP 25-25/Task 103 | Administration of Categorical Exclusions by State Departments of Transportation under NEPA | Final | |
| NCHRP 25-25/Task 104 | Streamlining Carbon Monoxide Project-Level Air Quality Analyses with Programmatic Agreements | Final | |
| NCHRP 25-25/Task 105 | A Guidebook for Communications between Transportation and Public Health Communities | Final | |
| NCHRP 25-25/Task 106 | Highway Noise and Historic Properties: A National Review of Effects and Mitigation Practices | Final | |
| NCHRP 25-25/Task 107 | Section 106 Delegation Programmatic Agreements: Review and Best Practices | Final | |
| NCHRP 25-25/Task 108 | Creating Lookup Tables to Streamline the Determination of Emission Reductions for CMAQ Projects | Final | |
| NCHRP 25-25/Task 109 | Successful Practices for Environmental Commitments in Public/Private Partnerships (P-3) and Design-Build (D-B) Contracts | Final | |
| NCHRP 25-25/Task 110 | Review of Historic Property Identification Surveys and Strategies for Managing Post-World War II Housing in Transportation Projects | Final | |
| NCHRP 25-25/Task 111 | Environmental Management System Perspectives For State DOTs | Final | |
| NCHRP 25-25/Task 112 | Enhancing the International Stormwater BMP Database to Serve as a Highway Specific BMP Database | Final | Cancelled. |
| NCHRP 25-25/Task 113 | Road Passages and Barriers for Small Terrestrial Wildlife: Summary and Repository of Design Examples | Final | |
| NCHRP 25-25/Task 114 | Integrating Tribal Expertise into Processes to Identify, Evaluate, and Record Cultural Resources | Final | |
| NCHRP 25-25/Task 115 | Estimates of Emissions Reductions from Future Fleet Changes for Use in Air Quality Models | Final | |
| NCHRP 25-25/Task 116 | Potential Section 106 Exempted Categories or Program Comments for Federal Highway Administration Projects: National Streamlining Opportunities | Final | |
| NCHRP 25-25/Task 117 | Valuing Wildlife Crossing Enhancements for Mitigation Credits | Final | |
| NCHRP 25-25/Task 118 | Context-Sensitive Design Options for Workhorse Bridges in Rural Historic Districts | Final | |
| NCHRP 25-25/Task 119 | Enhancing the International Stormwater BMP Database to Serve as a Highway Specific BMP Database | Final | |
| NCHRP 25-25/Task 120 | Use of the State Department of Transportation Portal to the International Stormwater BMP Database | Final | |
| NCHRP 25-25B | Research for the AASHTO Standing Committee on the Environment | Active | |
| NCHRP 25-27 | Evaluation of the Use and Effectiveness of Wildlife Crossings | Completed | |
| NCHRP 25-28 | Predicting and Mitigating Hydroacoustic Impacts on Fish from Pile Installation | Completed | The final report has been published as Research Results Digest 363. |
| NCHRP 25-29 | Developing Design and Management Guidelines for Historic Road Corridors | Completed | |
| NCHRP 25-29A | Guidelines for Design and Management of Historic Roads | Completed | The project final report is available as NCHRP Web-Only Document 189. |
| NCHRP 25-30 | Temporary Bridging to Avoid or Minimize Impacts to Waters and Wetlands During Highway Construction | Final | The results of this study have been published in NCHRP Research Results Digest 330 . |
| NCHRP 25-31 | Guidelines for Evaluating and Selecting Modifications to Existing Roadway Drainage Infrastructure to Improve Water Quality in Ultra-Urban Areas | Completed | |
| NCHRP 25-32 | Measuring and Removing Dissolved Metals from Storm Water in Highly Urbanized Areas | Completed | Research completed; to be published as NCHRP report 767 |
| NCHRP 25-33 | Evaluating Methodologies for Visual Impact Assessments | Final | Final report published as Report 741 |
| NCHRP 25-34 | Supplemental Guidance on the Application of FHWA's Traffic Noise Model (TNM) | Final | |
| NCHRP 25-35 | Guidebook for Designing and Managing Rights-of-Way for Carbon Sequestration and Biomass Generation | Completed | Completed. Published as NCHRP Report 804 with CRP-CD-165 |
| NCHRP 25-36 | Impacts of Land Use Strategies on Travel Behavior in Small Communities and Rural Areas | Final | Agency's Handbook is available as NCHRP Web-only Document 211 |
| NCHRP 25-37 | A Watershed Approach to Mitigating Stormwater Impacts | Final | |
| NCHRP 25-38 | Input Guidelines for Motor Vehicle Emissions Simulator Model | Final | Final deliverables are available as individual volumes of NCHRP Web-only Document 210 |
| NCHRP 25-39 | Environmental Performance Measures for State Departments of Transportation | Final | |
| NCHRP 25-40 | Long-Term Performance and Life-Cycle Costs of Stormwater Best Management Practices | Completed | Final report published as NCHRP Report 792. |
| NCHRP 25-41 | Guidance for Achieving Volume Reduction of Highway Runoff in Urban Areas | Completed | |
| NCHRP 25-42 | Bridge Stormwater Runoff Analysis and Treatment Options | Final | |
| NCHRP 25-43 | Navigating Multi-Agency NEPA Processes to Advance Multimodal Transportation Projects | Final | |
| NCHRP 25-44 | Field Evaluation of Reflected Noise from a Single Noise Barrier | Final | |
| NCHRP 25-45 | Mapping Heavy Vehicle Noise Source Heights for Highway Noise Analysis | Completed | |
| NCHRP 25-46 | Deploying Clean Truck Freight Strategies | Final | Published as NCHRP Report 862 |
| NCHRP 25-47 | How to Measure and Communicate the Value of Access Management | Final | |
| NCHRP 25-48 | Combined Interface for Project Level Air Quality Analysis | Final | |
| NCHRP 25-49 | Development of a Highway Construction Noise Prediction Model | Final | Complete. Final report available on project webpage and FHWA website. |
| NCHRP 25-50 | Prioritization Procedure for Proposed Road-Rail Grade Separation Projects along Specific Rail Corridors | Final | Published as NCHRP Report 901 |
| NCHRP 25-51 | Limitations of the Infiltration Approach to Stormwater Management in the Highway Environment | Final | Published as NCHRP Research Report 922 |
| NCHRP 25-52 | Meteorological Effects on Roadway Noise | Final | |
| NCHRP 25-53 | Approaches for Determining and Complying with TMDL Requirements Related to Roadway Stormwater Runoff | Final | |
| NCHRP 25-54 | Field Testing of BMPs Using Granulated Ferric Oxide Media to Remove Dissolved Metals in Roadway Stormwater Runoff | Final | |
| NCHRP 25-55 | Assessment of Regulatory Air Pollution Dispersion Models to Quantify the Impacts of Transportation Sector Emissions | Final | |
| NCHRP 25-56 | Methods for State DOTs to Reduce Greenhouse Gas Emissions from the Transportation Sector | Final | |
| NCHRP 25-57 | Breaking Barriers: Alternative Approaches to Avoiding and Reducing Highway Traffic Noise Impacts | Final | |
| NCHRP 25-58 | Commercial Properties from 1945 to 1980: Guidance for State DOTs and Their Partners for Historic Context Development, Identification, and Evaluation | Final | Project cancelled. |
| NCHRP 25-59 | Pollinator Habitat Conservation Along Roadways | Final | |
| NCHRP 25-60 | Watershed Approach to Mitigating Hydrologic Impacts of Transportation Projects | Final | |
| NCHRP 25-61 | Development of On-Bridge Stormwater Treatment Practices | Final | |
| NCHRP 25-62 | Improving the Efficiency and Consistency of Section 106 Compliance for State DOTs: Strategies for Project-Level Programmatic Agreements and Postwar Commercial Properties | Final | |
| NCHRP 25-63 | Handbook on Deterring and Excluding Bats from Transportation Structures | Active | Research in progress |
| NCHRP 25-64 | Considering Greenhouse Gas Emissions and Climate Change in Environmental Reviews: Resources for State DOTs | Final | Published as NCHRP WebResource 3 and NCHRP Web-Only Document 400 on 7/15/2024 |
| NCHRP 25-65 | Preparing Successful No-Effect and No-Adverse-Effect Section 106 Determinations: A Handbook for Transportation Cultural Resource Practitioners | Completed | In publication process |
| NCHRP 25-66 | Reviewing the REMEL Noise Database to Accommodate the Current Vehicle Fleet | Active | |
| NCHRP 25-67 | Guide to Mitigation of Adverse Effects on Cultural Resources | Active | |
| NCHRP 25-68 | Documenting and Verifying Environmental Commitments | Active | |
| NCHRP 25-69 | Guide to Increasing and Sustaining Native Flora in Roadside Vegetation | Active | Research in progress |
| NCHRP 25-70 | Evaluating Carbon Reduction in Project Selection and Planning | Pending | |
| NCHRP 25-71 | Prevention and Control of Wildfires Through Roadside Vegetation Management | Pending | |
| NCHRP 25-72 | Field Methods and Interlaboratory Tests to Establish the Accuracy and Precision of Measured Concentrations of Emerging Contaminants in Stormwater Runoff and Stormwater-Treatment System Effluent | Anticipated | In development |
| NCHRP 25-73 | Successful Community Impact Strategies During the Construction of Projects | Anticipated | In development |
| NCHRP 25-74 | Evaluating the Effects of Transportation Investments on Greenhouse Gas Emissions | RFP | |
| NCHRP 25-75 | Simplified Methodology for Risk-Based Air Quality Assessments of NEPA Alternatives | Anticipated | In development |