Assignment functionality takes location data and turns it into information by linking that location to scheduled piece of work (e.g. a transit trip or a delivery itinerary). It is a crucial, yet opaque component of an AVL system. Each AVL product will have a different take on the problem, with different requirements from input data and operator/supervisor interaction.
Assignment sits on a continuum between Explicit and Implicit or Inferred. Explicit assignments are made by an operator or system that assigns a piece of work to a vehicle. Assignments are often provided by a vehicle operator entering their assignment into a device on the vehicle, or a dispatch system with prior knowledge of which vehicle(s) will perform which assignment. Inferred assignments are made by a process that analyzes the vehicle’s recent behavior to guess what piece of work it is serving. Inferring assignments are more complicated in dense networks, where multiple assignments can be likely.
If you are procuring an CAD/AVL/RTPI system, questions to ask about its assignment system are:
What is the interaction that operators are expected to have with the system? Do they have to interact with a new device? What does that interface look like? Specifically, how many new keys do they have to press? Will there be labor relations issues as a result?
Does the system rely on assignment data from an external system (e.g dispatcher entry)?
What validation is done against operator or dispatcher entered data? Can an operator enter incorrect data?
What level of intelligence is on the vehicle? Most “computer-on-a-bus” solutions download the entire schedule to the bus and can store data for later transmission when losing connectivity. More simple on-board systems do not store any information on the vehicle; they send only the information they have. How/when are are data on vehicles synchronized?
How flexible can the system be when deviating from expectations? For example, how does it handle detours? What about extra unscheduled service?
What does the assignment system it telling you? Does it ever display expected (rather than actual) information? Does it tell you the difference between the two?