Access Nested JSON parameteres

Question

Im trying to get the Vin part from the JSON array.

{
  "results": [
    {
      "vehicle": {
        "ownershipCondition": "Used",
        "registration": "BX68NHL",
        "vin": "ZFA3120000JA60541",
        "make": "Fiat",
        "model": "500",
        "generation": "Hatchback (2015 - )"
      }
    }
  ]
}

I have tried using this but it doesnt work. Can anyone help.

foreach($result['results'] as $res)
{
    $currCar = $res['vehicle']['vin'];
    echo $currCar."\n";
}