| Abbreviation | Definition |
|---|---|
| IPSGA | Information, Position, Speed, Gear, Acceleration (motorcycles) |
| IPTA | Iowa Pupil Transportation Association |
| IPTV | Incidents Per Thousand Vehicles |
| IPV | Imperial Patrol Vehicle |
| IQ | Intermodal Quality |
| IR | Incident Report |
| IR | Interval Restriction |
| IRAN | Inspect and Repair As Necessary |
| IRBT | Integrated Rail Bus Transit (India) |
| IRCTC | Indian Railway Catering and Tourism Corporation (Ltd.) |
| IRDE | Intelligent Responsive Drive Engine |
| IRF | International Road Federation |
| IRI | International Roughness Index |
| IRIEEN | Indian Railways Institute of Electrical Engineering |
| IRIS | Incident Resolution Information System |
| IRIS | Integrated Road Information System |
| IRISL | Islamic Republic of Iran Shipping Lines |
| IRITM | Indian Railway Institute of Transportation Management |
| IROC | International Race Of Champions |
| IROP | IrRegular Operations Policy |