"mobile speed bump" meaning in English

{
  "forms": [
    {
      "form": "mobile speed bumps",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "mobile speed bump"
      },
      "expansion": "mobile speed bump (plural mobile speed bumps)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Road transport",
          "orig": "en:Road transport",
          "parents": [
            "Transport",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "A car that travels at the speed limit to prevent the cars behind from exceeding it."
      ],
      "id": "en-mobile_speed_bump-en-noun-2Lo2xZ3Y",
      "links": [
        [
          "car",
          "car"
        ],
        [
          "speed limit",
          "speed limit"
        ]
      ],
      "raw_glosses": [
        "(road transport) A car that travels at the speed limit to prevent the cars behind from exceeding it."
      ],
      "topics": [
        "road",
        "transport"
      ]
    }
  ],
  "word": "mobile speed bump"
}

{
  "forms": [
    {
      "form": "mobile speed bumps",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "mobile speed bump"
      },
      "expansion": "mobile speed bump (plural mobile speed bumps)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Road transport"
      ],
      "glosses": [
        "A car that travels at the speed limit to prevent the cars behind from exceeding it."
      ],
      "links": [
        [
          "car",
          "car"
        ],
        [
          "speed limit",
          "speed limit"
        ]
      ],
      "raw_glosses": [
        "(road transport) A car that travels at the speed limit to prevent the cars behind from exceeding it."
      ],
      "topics": [
        "road",
        "transport"
      ]
    }
  ],
  "word": "mobile speed bump"
}