Active tags are powered by an on-board battery enabling
higher power transmissions to cover longer distances. Reading
an active tag involves the reader continuously polling to determine
if any tags are within its reading range. Often, the reader
generates an EMF to signal that it is ready to read the active
tag. When the tag receives the poll read-request, it returns its
ID value. This pattern avoids wasting the active tag's battery
life; the power required to receive is far less than that required
to transmit a signal. Due to the much larger reading range for
an active tag than for a passive tag, more than one tag is likely
to be within reading range at a time. A reading protocol usually
exists to ensure only one tag is read at a time.

The most common uses of active RFID tags are in automatic
highway toll collection and in tracking railroad boxcars. Systems
such as EZ-Pass and FastPass use active RFID tags that
can be read at distances of up to 10 meters when located
behind the windshield of an automobile. Readers are positioned
above the lanes that are marked for use of the pass. As
the automobile equipped with the tag moves under the reader,
the tag is read and the ID number is identified with the tag
holder. For single toll positions such as for a toll bridge or tunnel,
the tag holder's account is debited immediately. For highway
tolls, the entrance reading is saved for processing with the
subsequent exit reading, at which time the tag holder's account
is debited for the calculated toll. The tag retains no data. The
use of active RFID tags has resulted in a 300 percent improvement
in these automated tollbooths' capacity compared with
manual toll collection.

In North America, all railroad freight cars are tagged with an
active RFID transponder as part of the Rail and Intermodal
Asset Tracking System. As the rail cars pass in front of readers
located at strategic rail switching yards scattered all over North
America, their identity is read and reported to a common tracking
system. This allows the system to track the location of all
freight cars in North America to the specific switching yard.
This information is used in billing freight car usage and in
scheduling and routing freight cars.