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GlossaryDispatch and call records

Automatic vehicle location

Automatic vehicle location reports response-vehicle positions to dispatch systems. Learn how AVL differs from unit status, caller location, and an arrival timestamp.

Automatic vehicle location, or AVL, is technology that reports a vehicle's position for dispatch and operational use. In public safety, it can help staff see where response resources are located. A displayed vehicle position is not the same as the unit's availability, an arrival confirmation, or a complete history of what personnel were doing.

Location supports a dispatch decision

AVL commonly uses the Global Positioning System, or GPS, to locate vehicles on a map. The Bureau of Justice Assistance describes its use in showing patrol-car positions to assist dispatch assignments. BJA technology glossary

Position is one piece of information. A nearby vehicle may already be committed to another task, may lack the needed capability, or may have an operational restriction. Knowing the location therefore does not establish that the resource was eligible for a new assignment.

AVL data also need a time reference. A map symbol represents a position reported at a particular moment, even if the interface looks continuously updated. For a precise claim about a vehicle's location, the record should include the observation time and the system's refresh behavior.

Example

Hypothetical example: At 2:00 p.m., a dispatch map shows two patrol vehicles near a road hazard. Unit A's most recent position was received at 1:59:55; Unit B's at 1:58:30. Unit A is available, while Unit B is handling another incident.

The map supports different conclusions for each resource. Unit A has a relatively recent reported position and an available status. Unit B's proximity alone does not make it an available alternative. Neither point proves when the unit reached the hazard, because assignment and arrival are separate events.

Common confusion

Automatic location identification, or ALI, concerns location information associated with a 911 caller. AVL concerns vehicles. Similar abbreviations do not make the underlying locations interchangeable.

A mobile data terminal can display or exchange dispatch information; it is not itself synonymous with AVL. Unit status describes an operational state such as assigned or on scene. A vehicle can remain in one location while its status changes.

Interpreting a map or export

Check update frequency, missing-position handling, and whether positions are actual reports or locations estimated by the display. Do not measure response time from map proximity alone. A route, stopped vehicle, or apparent gap needs additional evidence before it can explain service performance.

Public data may omit vehicle-level tracking entirely. An incident map generally shows event locations, which should not be assumed to be vehicle positions simply because both appear as points.

Sources