diff --git a/src/data/traffic.test.mjs b/src/data/traffic.test.mjs
index 23924448a..0e8ada30a 100644
--- a/src/data/traffic.test.mjs
+++ b/src/data/traffic.test.mjs
@@ -30,6 +30,28 @@ test('a superseded flow fetch is not an outage', () => {
   assert.equal(deriveTrafficFlowError(undefined), null);
 });
 
+test('hosted account limits and service failures name their own reason', () => {
+  const failure = (status, code) =>
+    deriveTrafficFlowError(
+      Object.assign(new Error(`TomTom flow unavailable (HTTP ${status})`), {
+        status,
+        code,
+      }),
+    );
+  assert.equal(
+    failure(429, 'USAGE_LIMIT_REACHED'),
+    'Monthly traffic allowance used',
+  );
+  assert.equal(failure(429, 'RATE_LIMITED'), 'Traffic rate limit reached');
+  assert.equal(failure(429, 'budget'), 'TomTom daily budget reached');
+  assert.equal(failure(503, 'no_key'), 'TomTom key unavailable');
+  assert.equal(failure(503, null), 'TomTom key unavailable');
+  assert.equal(
+    failure(503, 'USAGE_UNAVAILABLE'),
+    'Traffic service unavailable',
+  );
+});
+
 test('flow failures map onto short, specific reasons', () => {
   const reason = (message) => deriveTrafficFlowError(new Error(message));
   assert.equal(reason('flow tile 12/1/1: HTTP 503'), 'TomTom key unavailable');
diff --git a/src/i18n/locales/ar.json b/src/i18n/locales/ar.json
index b491c3c93..8a2b81e20 100644
--- a/src/i18n/locales/ar.json
+++ b/src/i18n/locales/ar.json
@@ -1749,6 +1749,9 @@
   "Hybrid": "هجين",
   "TomTom key unavailable": "مفتاح TomTom غير متاح",
   "TomTom daily budget reached": "بلغت الحصة اليومية لـ TomTom",
+  "Monthly traffic allowance used": "تم استهلاك حصة حركة المرور الشهرية",
+  "Traffic rate limit reached": "تم بلوغ حد طلبات حركة المرور",
+  "Traffic service unavailable": "خدمة حركة المرور غير متاحة",
   "TomTom upstream unreachable": "تعذّر الوصول إلى خادم TomTom",
   "TomTom flow unavailable": "تدفق TomTom غير متاح",
   "SIMULATED — {reason}": "محاكى — {reason}",
diff --git a/src/i18n/locales/de.json b/src/i18n/locales/de.json
index d01ff292f..837a87471 100644
--- a/src/i18n/locales/de.json
+++ b/src/i18n/locales/de.json
@@ -1667,6 +1667,9 @@
   "Hybrid": "Hybrid",
   "TomTom key unavailable": "TomTom-Schlüssel nicht verfügbar",
   "TomTom daily budget reached": "TomTom-Tagesbudget erreicht",
+  "Monthly traffic allowance used": "Monatliches Verkehrskontingent aufgebraucht",
+  "Traffic rate limit reached": "Verkehrs-Anfragelimit erreicht",
+  "Traffic service unavailable": "Verkehrsdienst nicht verfügbar",
   "TomTom upstream unreachable": "TomTom-Upstream nicht erreichbar",
   "TomTom flow unavailable": "TomTom-Verkehrsfluss nicht verfügbar",
   "SIMULATED — {reason}": "SIMULIERT – {reason}",
diff --git a/src/i18n/locales/es.json b/src/i18n/locales/es.json
index aa403f743..57aa09eb7 100644
--- a/src/i18n/locales/es.json
+++ b/src/i18n/locales/es.json
@@ -2274,6 +2274,9 @@
   "SIMULATED — {reason}": "SIMULADO — {reason}",
   "TomTom key unavailable": "Clave de TomTom no disponible",
   "TomTom daily budget reached": "Se alcanzó el límite diario de TomTom",
+  "Monthly traffic allowance used": "Cupo mensual de tráfico agotado",
+  "Traffic rate limit reached": "Límite de solicitudes de tráfico alcanzado",
+  "Traffic service unavailable": "Servicio de tráfico no disponible",
   "TomTom upstream unreachable": "Servidor de TomTom inaccesible",
   "TomTom flow unavailable": "Flujo de TomTom no disponible",
   "API key rejected — check AISSTREAM_API_KEY": "Clave de API rechazada — revisa AISSTREAM_API_KEY",
diff --git a/src/i18n/locales/fr.json b/src/i18n/locales/fr.json
index b3ae72189..bfd2a5975 100644
--- a/src/i18n/locales/fr.json
+++ b/src/i18n/locales/fr.json
@@ -1105,6 +1105,9 @@
   "Hybrid": "Hybride",
   "TomTom key unavailable": "Clé TomTom indisponible",
   "TomTom daily budget reached": "Quota quotidien TomTom atteint",
+  "Monthly traffic allowance used": "Quota mensuel de trafic épuisé",
+  "Traffic rate limit reached": "Limite de requêtes de trafic atteinte",
+  "Traffic service unavailable": "Service de trafic indisponible",
   "TomTom upstream unreachable": "Serveur TomTom injoignable",
   "TomTom flow unavailable": "Flux TomTom indisponible",
   "SIMULATED — {reason}": "SIMULÉ — {reason}",
diff --git a/src/i18n/locales/it.json b/src/i18n/locales/it.json
index 4c69e1d4c..74c0d01aa 100644
--- a/src/i18n/locales/it.json
+++ b/src/i18n/locales/it.json
@@ -1105,6 +1105,9 @@
   "Hybrid": "Ibrido",
   "TomTom key unavailable": "Chiave TomTom non disponibile",
   "TomTom daily budget reached": "Budget giornaliero TomTom esaurito",
+  "Monthly traffic allowance used": "Quota mensile del traffico esaurita",
+  "Traffic rate limit reached": "Limite di richieste del traffico raggiunto",
+  "Traffic service unavailable": "Servizio traffico non disponibile",
   "TomTom upstream unreachable": "Servizio TomTom irraggiungibile",
   "TomTom flow unavailable": "Flusso TomTom non disponibile",
   "SIMULATED — {reason}": "SIMULATO: {reason}",
diff --git a/src/i18n/locales/ja.json b/src/i18n/locales/ja.json
index 9a053f869..932d851e2 100644
--- a/src/i18n/locales/ja.json
+++ b/src/i18n/locales/ja.json
@@ -1073,6 +1073,9 @@
   "Hybrid": "ハイブリッド",
   "TomTom key unavailable": "TomTomキーを利用できません",
   "TomTom daily budget reached": "TomTomの1日の上限に達しました",
+  "Monthly traffic allowance used": "今月の交通情報の上限に達しました",
+  "Traffic rate limit reached": "交通情報のリクエスト上限に達しました",
+  "Traffic service unavailable": "交通情報サービスを利用できません",
   "TomTom upstream unreachable": "TomTomのサービスに接続できません",
   "TomTom flow unavailable": "TomTomの交通流を利用できません",
   "SIMULATED — {reason}": "シミュレーション：{reason}",
diff --git a/src/i18n/locales/pt.json b/src/i18n/locales/pt.json
index 79c507759..e71f144d5 100644
--- a/src/i18n/locales/pt.json
+++ b/src/i18n/locales/pt.json
@@ -1103,6 +1103,9 @@
   "Hybrid": "Híbrido",
   "TomTom key unavailable": "Chave do TomTom indisponível",
   "TomTom daily budget reached": "Limite diário do TomTom atingido",
+  "Monthly traffic allowance used": "Cota mensal de trânsito esgotada",
+  "Traffic rate limit reached": "Limite de solicitações de trânsito atingido",
+  "Traffic service unavailable": "Serviço de trânsito indisponível",
   "TomTom upstream unreachable": "Servidor do TomTom inacessível",
   "TomTom flow unavailable": "Fluxo do TomTom indisponível",
   "SIMULATED — {reason}": "SIMULADO — {reason}",
diff --git a/src/i18n/locales/ru.json b/src/i18n/locales/ru.json
index 11fddb3e9..6573ad11b 100644
--- a/src/i18n/locales/ru.json
+++ b/src/i18n/locales/ru.json
@@ -2313,6 +2313,9 @@
   "SIMULATED — {reason}": "СИМУЛЯЦИЯ — {reason}",
   "TomTom key unavailable": "Ключ TomTom недоступен",
   "TomTom daily budget reached": "Исчерпан дневной лимит TomTom",
+  "Monthly traffic allowance used": "Месячный лимит данных о трафике исчерпан",
+  "Traffic rate limit reached": "Достигнут лимит запросов данных о трафике",
+  "Traffic service unavailable": "Сервис данных о трафике недоступен",
   "TomTom upstream unreachable": "Сервер TomTom не отвечает",
   "TomTom flow unavailable": "Поток TomTom недоступен",
   "API key rejected — check AISSTREAM_API_KEY": "Ключ API отклонён — проверьте AISSTREAM_API_KEY",
diff --git a/src/i18n/locales/uk.json b/src/i18n/locales/uk.json
index c0fab8533..18ea8dc4f 100644
--- a/src/i18n/locales/uk.json
+++ b/src/i18n/locales/uk.json
@@ -1120,6 +1120,9 @@
   "Hybrid": "Гібрид",
   "TomTom key unavailable": "Ключ TomTom недоступний",
   "TomTom daily budget reached": "Вичерпано денний ліміт TomTom",
+  "Monthly traffic allowance used": "Місячний ліміт даних про трафік вичерпано",
+  "Traffic rate limit reached": "Досягнуто ліміту запитів даних про трафік",
+  "Traffic service unavailable": "Сервіс даних про трафік недоступний",
   "TomTom upstream unreachable": "Сервер TomTom не відповідає",
   "TomTom flow unavailable": "Потік TomTom недоступний",
   "SIMULATED — {reason}": "ІМІТАЦІЯ — {reason}",
diff --git a/src/i18n/locales/zh-CN.json b/src/i18n/locales/zh-CN.json
index 8687af790..8d09b74a3 100644
--- a/src/i18n/locales/zh-CN.json
+++ b/src/i18n/locales/zh-CN.json
@@ -1049,6 +1049,9 @@
   "Hybrid": "混合",
   "TomTom key unavailable": "TomTom 密钥不可用",
   "TomTom daily budget reached": "已达 TomTom 每日配额",
+  "Monthly traffic allowance used": "本月交通流量额度已用完",
+  "Traffic rate limit reached": "已达到交通数据请求频率上限",
+  "Traffic service unavailable": "交通服务不可用",
   "TomTom upstream unreachable": "TomTom 上游服务无法连接",
   "TomTom flow unavailable": "TomTom 路况不可用",
   "SIMULATED — {reason}": "模拟——{reason}",
diff --git a/src/i18n/locales/zh-Hant.json b/src/i18n/locales/zh-Hant.json
index a95e71dd5..30801f0f9 100644
--- a/src/i18n/locales/zh-Hant.json
+++ b/src/i18n/locales/zh-Hant.json
@@ -1044,6 +1044,9 @@
   "Hybrid": "混合",
   "TomTom key unavailable": "TomTom 密鑰不可用",
   "TomTom daily budget reached": "已達 TomTom 每日配額",
+  "Monthly traffic allowance used": "本月交通流量額度已用完",
+  "Traffic rate limit reached": "已達交通資料請求頻率上限",
+  "Traffic service unavailable": "交通服務無法使用",
   "TomTom upstream unreachable": "TomTom 上游服務無法連接",
   "TomTom flow unavailable": "TomTom 路況不可用",
   "SIMULATED — {reason}": "模擬——{reason}",
diff --git a/src/layers/traffic/flow.js b/src/layers/traffic/flow.js
index 2064c10ce..caf8aede2 100644
--- a/src/layers/traffic/flow.js
+++ b/src/layers/traffic/flow.js
@@ -38,7 +38,15 @@ export function createFlow({ state: layerState, services, parts, source }) {
     const status = Number.isFinite(error.status)
       ? error.status
       : Number(message.match(/HTTP (\d{3})/)?.[1]);
+    const code = typeof error.code === 'string' ? error.code : null;
     // English in state; trafficFeedPresentation translates it for the panel.
+    // A hosted deployment limits each account (code from the server); the
+    // local proxy has one daily budget (`budget`) and answers `no_key`.
+    if (code === 'USAGE_LIMIT_REACHED')
+      return msg('Monthly traffic allowance used');
+    if (code === 'RATE_LIMITED') return msg('Traffic rate limit reached');
+    if (status === 503 && code && code !== 'no_key')
+      return msg('Traffic service unavailable');
     if (status === 503) return msg('TomTom key unavailable');
     if (status === 429) return msg('TomTom daily budget reached');
     if (status === 502 || status === 504)
diff --git a/src/layers/traffic/flowSource.js b/src/layers/traffic/flowSource.js
index 12e746e43..e5402cf12 100644
--- a/src/layers/traffic/flowSource.js
+++ b/src/layers/traffic/flowSource.js
@@ -11,6 +11,26 @@ const FLOW_TILE_PATH = (z, x, y) => `/api/tomtom/flow/${z}/${x}/${y}.pbf`;
  * (STALE-BUDGET once the daily budget is spent, STALE-ERROR when TomTom
  * fails), and when the proxy fetched it.
  */
+/**
+ * The machine-readable reason a failed tile carries: `code` (hosted usage,
+ * e.g. USAGE_LIMIT_REACHED or RATE_LIMITED) or the local proxy's `error`
+ * (`no_key`, `budget`). Only short identifiers are kept; prose is ignored.
+ */
+async function failureCode(response) {
+  if (!/json/i.test(response.headers?.get?.('content-type') || '')) return null;
+  try {
+    const text = await response.text();
+    if (text.length > 4096) return null;
+    const body = JSON.parse(text);
+    const code = body?.code ?? body?.error;
+    return typeof code === 'string' && /^[A-Za-z_]{1,40}$/.test(code)
+      ? code
+      : null;
+  } catch {
+    return null;
+  }
+}
+
 function tileFreshness(response) {
   const status = response.headers?.get?.('x-tomtom-cache') || '';
   const fetchedAt = Number(response.headers?.get?.('x-tomtom-fetched-at'));
@@ -60,7 +80,16 @@ export function createFlowTileSource({
     },
     fetchImpl: async (url, init) => {
       const response = await fetchImpl(url, init);
-      if (response.ok && !init.signal.aborted) {
+      if (!response.ok) {
+        const code = await failureCode(response);
+        await response.body?.cancel().catch(() => {});
+        throw Object.assign(
+          // Classified for display by deriveTrafficFlowError.
+          new Error(`TomTom flow unavailable (HTTP ${response.status})`),
+          { status: response.status, code },
+        );
+      }
+      if (!init.signal.aborted) {
         const path = String(url);
         const entry = {
           mark: tileFreshness(response),
diff --git a/src/layers/traffic/source.test.mjs b/src/layers/traffic/source.test.mjs
index 779164b7c..e45f5ef0f 100644
--- a/src/layers/traffic/source.test.mjs
+++ b/src/layers/traffic/source.test.mjs
@@ -1050,3 +1050,29 @@ test('cancelling a flow body releases its freshness before a new request', async
   assert.equal(getEventListeners(requestSignal, 'abort').length, 0);
   assert.equal(source.getFlowSessionStats().cacheEntries, 0);
 });
+
+test('a failed flow tile carries the server reason for its label', async () => {
+  for (const [status, body, code] of [
+    [
+      429,
+      { error: 'Monthly usage limit reached', code: 'USAGE_LIMIT_REACHED' },
+      'USAGE_LIMIT_REACHED',
+    ],
+    [
+      429,
+      { error: 'Request rate limit reached', code: 'RATE_LIMITED' },
+      'RATE_LIMITED',
+    ],
+    [503, { error: 'no_key' }, 'no_key'],
+    [503, { error: 'Usage enforcement is temporarily unavailable' }, null],
+  ]) {
+    const source = createFlowTileSource({
+      fetchImpl: async () => Response.json(body, { status }),
+    });
+    await assert.rejects(source.fetchFlowForBounds(bounds), (error) => {
+      assert.equal(error.status, status);
+      assert.equal(error.code, code);
+      return true;
+    });
+  }
+});