North American agencies and volunteer groups that search for people who've wandered away and become lost are using RFID-enabled wristbands and handheld readers—a combination that has drastically reduced the time it can take to find the missing.

On average, searches have been reduced to a half-hour or less. The system uses wristbands and readers operating within the very high frequency (VHF) range. VHF allows for a read range of about a mile on the ground, and even greater distances from the air. has 566 agencies participating in 41 U.S. states and one Canadian province. monitor between 10,000 and 15,000 individuals.

RFID helps volunteers search for individuals—primarily Alzheimer's sufferers or those with autism—who had wandered away from their caregivers. In such cases, search-and-rescue personnel would sweep the area by walking or driving around the missing person's home. The average missing person walks at a speed of about 4 miles per hour, and the search could take hours or more,

Such search efforts can be vastly expedited with the use of RFID-enabled wristbands and handheld interrogators. Each wristband can also be worn on the ankle or attached to a shoe, and comes with an active RFID chip and antenna, as well as a battery with a one-month lifespan. The chip is set to constantly transmit its unique ID at a specific frequency within the range of 216 to 217 MHz.

If, however, several wristbands beacon at the same frequency, the ID number helps differentiate the identities of those wearing the wristbands.

When someone is reported missing, the search agency dispatches personnel, either on foot or in cars, with handheld RFID readers. The searchers set the interrogators to the appropriate frequency for the missing person's wristband and begin combing the area. "The [reader] chirps, and the ID number shows up on the screen, After confirming the ID number, rescue personnel begin following the signal, which grows stronger as they approach the individual, indicated by a louder chirp.

The average time required to locate and recover a missing person with the Lifesaver program is less than 30 minutes. So far, the program has been used in about 1,500 searches nationwide, and every search has led to a recovery.