Configured receiving events via the event.forward.url parameter

I receive the following json for the "ignitionOff" event

...
    ["type"]=>
    string(11) "ignitionOff"
    ["eventTime"]=>
    string(29) "2024-02-14T14:38:23.000+00:00"
...	
  }
  ["position"]=>
  array(18) {
    ["id"]=>
    int(86298)
    ["attributes"]=>
    array(19) {
...	
      ["distance"]=>
      float(0)
      ["totalDistance"]=>
      float(1727316.9924292939)
      ["hours"]=>
      int(481592860)
    }

Why distance =0 ?
In what units are the totalDistance and hours values?

The position section has an "odometer" field. In what units is this?