| Glossary Word | | Glossary Description | | |
| UKPMS | | The United Kingdom Pavement Management System defines standard methods for assessing highways. |
| |
| Ultra High Frequency (UHF-FM) | | Radio frequencies from 300 Megahertz (MHz) to 3,000 MHz with a normal range of less than 50 miles. Radio frequency common to military aircraft and used in the logistics radio system. The most common frequencies used by fire and public safety are from 406 MHz to 512 MHz. |
| |
| Unacceptable Risk | | Level of risk as determined by the risk management process which cannot be mitigated to an acceptable safe level. |
| |
| Uncontrolled Airport | | Airport not having an approved agency with radio communications to direct aircraft take-offs and landings. |
| |
| Uncontrolled Fire | | Any fire which threatens to destroy life, property, or natural resources, and (a) is not burning within the confines of firebreaks, or (b) is burning with such intensity that it could not be readily extinguished with ordinary tools commonly available. |
| |
| Underburn | | A fire that consume surface fuels but not the overstory canopy. |
