diff --git a/.env.local.example b/.env.local.example
index 1972429..b34d807 100644
--- a/.env.local.example
+++ b/.env.local.example
@@ -12,3 +12,7 @@ DB_PORT=3306
 DB_USER=
 DB_PASSWORD=
 DB_NAME=
+# Local development uses the public OneOS endpoint; the ECS private IP is not reachable locally.
+ONEOS_MILEAGE_API_BASE_URL=https://open.d.lnoneos.com
+ONEOS_MILEAGE_API_KEY=
+ONEOS_MILEAGE_API_TIMEOUT_MS=20000
diff --git a/src/server/routes/mileage/cache.ts b/src/server/routes/mileage/cache.ts
index a54f227..045a0cb 100644
--- a/src/server/routes/mileage/cache.ts
+++ b/src/server/routes/mileage/cache.ts
@@ -52,7 +52,7 @@ export interface RangeMileageResult {
 }
 
 async function fetchTargetRows(): Promise<TargetRow[]> {
-  return loadMonitoringTargetRows(pool).then(([rows]) => rows as TargetRow[]);
+  return loadMonitoringTargetRows(pool).then(rows => rows as unknown as TargetRow[]);
 }
 
 export async function refreshMonitoringCache(): Promise<void> {
diff --git a/src/server/routes/mileage/monitoring.test.ts b/src/server/routes/mileage/monitoring.test.ts
new file mode 100644
index 0000000..549303e
--- /dev/null
+++ b/src/server/routes/mileage/monitoring.test.ts
@@ -0,0 +1,45 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import pool from '../../db/mysql.js';
+import monitoring from './monitoring.js';
+import { clearOneOsMileageCache } from './oneos-api.js';
+
+test('single-day monitoring merges all target rows and handles an empty target table', async (t) => {
+  const previousUrl = process.env.ONEOS_MILEAGE_API_BASE_URL;
+  const previousKey = process.env.ONEOS_MILEAGE_API_KEY;
+  process.env.ONEOS_MILEAGE_API_BASE_URL = 'https://oneos.test';
+  process.env.ONEOS_MILEAGE_API_KEY = 'test-key';
+  t.after(() => {
+    if (previousUrl === undefined) delete process.env.ONEOS_MILEAGE_API_BASE_URL;
+    else process.env.ONEOS_MILEAGE_API_BASE_URL = previousUrl;
+    if (previousKey === undefined) delete process.env.ONEOS_MILEAGE_API_KEY;
+    else process.env.ONEOS_MILEAGE_API_KEY = previousKey;
+    clearOneOsMileageCache();
+  });
+  let targets = [
+    { id: 1, target_name: '目标A', plate_number: '粤A10001' },
+    { id: 2, target_name: '目标B', plate_number: '粤A10001' },
+  ];
+  t.mock.method(pool, 'query', async (sql: string) => {
+    if (sql.includes('tab_mileage_assessment_target')) return [targets, []];
+    assert.ok(sql.includes('FROM vehicle_info vi'));
+    return [[{ plate: '粤A10001', vin: 'test-vin' }], []];
+  });
+  t.mock.method(globalThis, 'fetch', async (_url: unknown, init: RequestInit) => {
+    const { date } = JSON.parse(String(init.body));
+    return Response.json({ code: 'SUCCESS', data: [{
+      plateNumber: '粤A10001', date, status: 'NORMAL',
+      dailyMileageKm: 12, totalMileageKm: 100, sourceProtocol: 'GB32960',
+    }] });
+  });
+  for (const expectedTargets of [['目标A', '目标B'], []]) {
+    clearOneOsMileageCache();
+    const response = await monitoring.request('/?startDate=2026-09-16&endDate=2026-09-16&sourcePriority=instrument');
+    assert.equal(response.status, 200);
+    const payload = await response.json();
+    assert.equal(payload.total, 1);
+    assert.equal(payload.vehicles[0].dailyKm, 12);
+    assert.deepEqual(payload.vehicles[0].targetNames, expectedTargets);
+    targets = [];
+  }
+});