highway=footway turns into a driveable lane

[dabreegster]

https://www.openstreetmap.org/way/150133153 yields:

{
  "highway": "footway",
  "lit": "yes",
  "smoothness": "good",
  "lanes": [
    {
      "type": "travel",
      "direction": "both",
      "designated": "motor_vehicle",
      "width": 3.0
    },
    {
      "type": "separator",
      "markings": [
        {
          "style": "solid_line",
          "width": 0.2,
          "color": "white"
        }
      ]
    }
  ]
}

[dabreegster]

Reported by @RobinLovelace