{
  "annotation_id": "3329448c-05e4-4182-92e3-c87e7027e737",
  "date_created": "2026-03-02T18:01:07.610000Z",
  "date_modified": "2026-03-02T18:01:07.610000Z",
  "file_hash": "e5d2b293fed386b2dd6c808fb0877a77ce09792a954f17a995a3f3414ef47044",
  "private": false,
  "record": {
    "abstract": "The urban road networks of the 20 largest German cities have been analysed,\nbased on a detailed database providing the geographical positions as well as\nthe travel-times for network sizes up to 37,000 nodes and 87,000 links. As the\nhuman driver recognises travel-times rather than distances, faster roads appear\nto be \u0027shorter\u0027 than slower ones. The resulting metric space has an effective\ndimension d\u003e2, which is a significant measure of the heterogeneity of road\nspeeds. We found that traffic strongly concentrates on only a small fraction of\nthe roads. The distribution of vehicular flows over the roads obeys a power\nlaw, indicating a clear hierarchical order of the roads. Studying the cellular\nstructure of the areas enclosed by the roads, the distribution of cell sizes is\nscale invariant as well.",
    "arxiv_id": "physics/0603257",
    "authors": [
      "Stefan L\u00e4mmer",
      "Bj\u00f6rn Gehlsen",
      "Dirk Helbing"
    ],
    "categories": [
      "physics.soc-ph"
    ],
    "doi": "10.1016/j.physa.2006.01.051",
    "journal_ref": "S. L\\\"ammer, B. Gehlsen, and Dirk Helbing (2006) Scaling laws in\n  the spatial structure of urban road networks, Physica A 363(1) 89-95",
    "title": "Scaling laws in the spatial structure of urban road networks",
    "url": "https://arxiv.org/abs/physics/0603257"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "1958e7ce-9287-4506-a848-05f1f8d6afcc",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}