---
title: Tracking Info Assigned
slug: fourkites-api-reference/tracking-info-assigned
description: Learn how updates to a load can be easily triggered based on specific criteria, like assigning truck, trailer, rail equipment, or driver phone number. Our document shares a comprehensive JSON example of a tracking info update and elucidates field definiti
createdAt: 2023-04-14T06:09:03.000Z
---

The update is triggered when a truck, trailer, rail equipment, or driver phone number is assigned to a load.

```json
{
    "MessageType" : "TRACKING_INFO_UPDATE",
    "FourKitesLoadId" : 1234,
    "LoadNumber" : "BOL12345",
    "ProNumber" : "PRO123",
    "Shipper" : "test-shipper",
    "Carrier" : "test-carrier",
    "Scac" : "ABCD",
    "Tags" : ["tag1", "tag2"],
    "ReferenceNumbers" : ["ref1", "ref2"],
    "Truck" : "6005",
    "Trailer" : "None",
    "RailEquipment" : "None",
    "DriverNumber" : "None",
    "DeviceID": "541634",
    "Timestamp" : "2015-10-01T16:00:00-05:00",
    "Timezone" : "America/New_York",
    "TimezoneShortName" : "UTC",
    "TimezoneOffset" : 0
}
```

:::hint{type="info"}
**Note**: Get in touch with your Customer Success Manager at FourKites to know how to pass the DeviceID during load creation and have the same included in this callback.
:::

## Field Definitions

| **Field Name**      | **Description**                                                                                                                                                         | **Key Always Present?** | **Conditions for the Key to be Present**                                                                                                                                                                                                    | **Data Type**             | **Max Length**                                            |
| ------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------- | --------------------------------------------------------- |
| `FourKitesLoadId`   | Unique load identifier of the load from the FourKites system that the stop belongs to                                                                                   | Yes                     | N/A                                                                                                                                                                                                                                         | Number                    | 20                                                        |
| `LoadNumber`        | Unique shipment identifier from shipper's system                                                                                                                        | Yes                     | N/A                                                                                                                                                                                                                                         | String                    | 65535                                                     |
| `ProNumber`         | Shipment's PRO #                                                                                                                                                        | Yes                     | N/A                                                                                                                                                                                                                                         | Number                    | 10                                                        |
| `Shipper`           | Unique shipper ID from FourKites                                                                                                                                        | Yes                     | N/A                                                                                                                                                                                                                                         | String                    | No max, but realistically, not longer than 200 characters |
| `Carrier`           | Unique carrier identifier from FourKites system                                                                                                                         | Yes                     | N/A                                                                                                                                                                                                                                         | String                    | 1024                                                      |
| `Scac`              |                                                                                                                                                                         | Yes                     | N/A                                                                                                                                                                                                                                         | Alpha/Numeric             | 4                                                         |
| `Tags`              | Array of tags associated with the load (empty list when tags are not present)                                                                                           | Yes                     | N/A                                                                                                                                                                                                                                         | Array of string           | 50 for each tag                                           |
| `ReferenceNumbers`  |                                                                                                                                                                         | Yes                     | N/A                                                                                                                                                                                                                                         | Array of string           | No max                                                    |
| `Truck`             | Truck number assigned to the load                                                                                                                                       | Yes                     | N/A                                                                                                                                                                                                                                         | String                    | 30                                                        |
| `Trailer`           | Trailer number assigned to the load                                                                                                                                     | Yes                     | N/A                                                                                                                                                                                                                                         | String                    | 1024                                                      |
| `RailEquipment`     | Rail equipment number assigned to the load                                                                                                                              | Yes                     | Will be mapped if the railequipment number is not null and rail equipment initial not null.                                                                                                                                                 |                           |                                                           |
| `DriverNumber`      | Driver number assigned to the load                                                                                                                                      | Yes                     | The DriverNumber field will be mapped if the newdriverphone is not null. The first 5 numbers will be hidden, last four numbers will be visible. If the value is not present and the driver number is present then the value will be "null". | String                    | 10                                                        |
| `DeviceID`          | Device id assigned to the load                                                                                                                                          | Yes                     | N/A                                                                                                                                                                                                                                         | String                    |                                                           |
| `Timestamp`         | Time when one of the three actions was performed that triggered the callback                                                                                            | Yes                     | N/A                                                                                                                                                                                                                                         | String in DateTime format |                                                           |
| `Timezone`          | Local Timezone of the stop in which Timestamp is specified                                                                                                              | Yes                     | N/A                                                                                                                                                                                                                                         | String                    | 50                                                        |
| `TimezoneShortName` | Will be hard coded to "UTC"                                                                                                                                             | Yes                     | N/A                                                                                                                                                                                                                                         | String                    | 5                                                         |
| `TimezoneOffset`    | Number of seconds the time zone is ahead of UTC time. For western hemisphere, time zones will be represented in negative values indicating that the time is behind UTC. | Yes                     | N/A                                                                                                                                                                                                                                         | \[+/-]Digits              | 10                                                        |
| `VesselName`        |                                                                                                                                                                         | Yes                     | For Ocean Loads.                                                                                                                                                                                                                            | String                    | 1024                                                      |
| `IMO`               |                                                                                                                                                                         | Yes                     | For Ocean Loads.                                                                                                                                                                                                                            |                           |                                                           |
| `MMSI`              |                                                                                                                                                                         | Yes                     | For Ocean Loads.                                                                                                                                                                                                                            |                           |                                                           |
| `ContainerNumber`   |                                                                                                                                                                         | No                      | For Ocean Loads.                                                                                                                                                                                                                            | String                    | 1024                                                      |