| TCRP D-01 | Rail-Corrugation Mitigation in Transit | Completed | |
| TCRP D-02 | Derailment of Transit Vehicles in Special Trackwork | Completed | |
| TCRP D-03 | Tunnel Track Reconstruction Methods Using Precast Concrete Systems | Completed | |
| TCRP D-03A | Tunnel Track Reconstruction Methods Using Precast Concrete Systems | Completed | |
| TCRP D-04 | Visual Impact of Overhead Contact Systems for Electric Transit Vehicles | Completed | |
| TCRP D-05 | Performance of Direct-Fixation Track Structure | Completed | |
| TCRP D-06 | Track Design Handbook for Light Rail Transit | Completed | |
| TCRP D-07 | Joint Rail Transit Research with the Association of American Railroads/Transportation Technology Center, Inc. | Active | |
| TCRP D-08 | Improving Pedestrian Safety at Unsignalized Roadway Crossings | Completed | |
| TCRP D-09 | Transit Vehicles and Facilities on Streets and Highways | Final | |
| TCRP D-10 | Audible Signals for Pedestrian Safety in Light Rail Transit Environments | Completed | The revised final report has been published as TCRP Research Results Digest 84 and Web-Only Document 35. |
| TCRP D-11 | Design, Operation, and Safety of At-Grade Crossings of Exclusive Busways | Final | |
| TCRP D-12 | Ground-Borne Noise and Vibration in Buildings Caused by Rail Transit | Final | |
| TCRP D-13 | A Guide for Implementing Bus-On-Shoulder (BOS) Systems | Completed | |
| TCRP D-14 | Track Design Handbook For Light Rail Transit, Second Edition | Completed | |
| TCRP D-15 | Effective Practices for the Protection of Transportation Infrastructure from Cyber Incidents | Completed | |
| TCRP D-16 | Improving the Safety and Sustainability of Stray Current Control of DC-Powered Rail Transit Systems | Completed | |
| TCRP D-17 | Detecting and Mitigating Low-Level DC Leakage and Fault Currents in Transit Systems | Completed | |
| TCRP D-18 | A Transit Agency Guide to Evaluating Secondary Train Detection/Protection Systems in Communications-Based Train Control (CBTC) Systems | Completed | |
| TCRP D-19 | Detecting and Mitigating Low-Level DC Fault Currents in Transit Systems (Phase II TCRP Project D-17) | Active | |
| TCRP D-20 | Investigation and Mitigation of Insulated Joint Electrical Failure | Pending | |
| TCRP D-21 | Planning for the Future of Intermodal Passenger Facilities: Guide and Decision-Making Framework | Active | |
| TCRP D-22 | A Frog Design Primer and Research Roadmap | Pending | |
| TCRP D-23 | Manual for Planning and Constructing a Small, Rural, or Tribal Transit Facility | Pending | |
| TCRP D-24 | Determination of Actual Derailment Loads on Transit Bridges | Pending | |
| TCRP D-25 | Preparation of a Manuscript for Publication of the Track Design Handbook for Light Rail Transit, 3rd Edition | Anticipated | In development |
| TCRP D-26 | Develop a Rational Approach to Performing Rail Structure Interaction Analysis (RSI) and for Using the Results of the Analysis in Transit Bridge Design | Anticipated | In development |