| Abbreviation | Definition |
|---|---|
| HSCR | Historical Stock Car Racing |
| HSR | Historic Sportscar Racing |
| HSRR | Historic Scale Racing Replicas |
| HTNA | Hampton Terrace Neighborhood Association |
| HURA | Heads Up Racing Association |
| HVR | High Voltage Racer |
| HWR | Heavy Weight Racing |
| HWTR | Hot Wheels Turbo Racing |
| HYRA | Hawaii Yacht Racing Association |
| IBRA | International Barrel Racing Association |
| IBRA | International Blokart Racing Association |
| IBRA | Iowa Bicycle Racing Association |
| IDCR | International Drift Championship Racing |
| IDRA | International Drone Racing Association |
| IDRA | Island Drag Racing Association |
| IDRC | Import Drag Racing Circuit |
| IDRF | Indonesia Drone Racing Federation |
| IEV | Intracellular Enveloped Virus |
| IFMAR | International Federation of Model Automobile Racing |
| IFMR | Internationaux de France de Match Racing |