diff --git a/services/nginx/app/tests/Api/VehiclesApiTest.php b/services/nginx/app/tests/Api/VehiclesApiTest.php
new file mode 100644
index 00000000..2298e39f
--- /dev/null
+++ b/services/nginx/app/tests/Api/VehiclesApiTest.php
@@ -0,0 +1,96 @@
+<?php
+
+declare(strict_types=1);
+
+usesApiSuite();
+
+it('returns the newest vehicle last_order_id that still has order items', function (): void {
+    api_test_covers('GET /vehicles', 'happy');
+
+    $session = api_fixtures()->createUserSession(['list_own_vehicles']);
+    $department = api_fixtures()->createDepartment(['name' => 'Vehicle API Department']);
+    $vehicle = api_fixtures()->createVehicle([
+        'customer_id' => $session['user']['customer_number'],
+        'type' => 53,
+        'reg' => 'SIDSTEV1',
+        'reference' => 'VEHICLE-LAST-WASH',
+    ]);
+
+    $olderOrder = api_fixtures()->createOrder([
+        'customer_id' => $session['user']['customer_number'],
+        'cashier_id' => $session['user']['id'],
+        'department_id' => $department['id'],
+        'reference' => 'OLDER-ORDER',
+        'reg_1' => $vehicle['reg'],
+    ]);
+    api_fixtures()->createOrderItem([
+        'order_id' => $olderOrder['id'],
+        'product_id' => 53,
+        'cashier_id' => $session['user']['id'],
+        'price' => 599,
+        'quantity' => 1,
+    ]);
+
+    $newerOrder = api_fixtures()->createOrder([
+        'customer_id' => $session['user']['customer_number'],
+        'cashier_id' => $session['user']['id'],
+        'department_id' => $department['id'],
+        'reference' => 'NEWER-ORDER',
+        'reg_1' => $vehicle['reg'],
+    ]);
+
+    $response = api_client()->get('/vehicles?id=' . $vehicle['id'], $session['headers']);
+
+    $response
+        ->assertStatus(200)
+        ->assertEnvelope()
+        ->assertSuccess();
+
+    expect($newerOrder['id'])->toBeGreaterThan($olderOrder['id']);
+    expect($response->data())->toMatchArray([
+        'id' => $vehicle['id'],
+        'reg' => $vehicle['reg'],
+        'last_order_id' => $olderOrder['id'],
+    ]);
+});
+
+it('returns a null vehicle last_order_id when no order with items exists', function (): void {
+    api_test_covers('GET /vehicles', 'happy');
+
+    $session = api_fixtures()->createUserSession(['list_own_vehicles']);
+    $department = api_fixtures()->createDepartment(['name' => 'Vehicle API Department Null']);
+    $vehicle = api_fixtures()->createVehicle([
+        'customer_id' => $session['user']['customer_number'],
+        'type' => 53,
+        'reg' => 'SIDSTEV2',
+        'reference' => 'VEHICLE-NO-LAST-WASH',
+    ]);
+
+    api_fixtures()->createOrder([
+        'customer_id' => $session['user']['customer_number'],
+        'cashier_id' => $session['user']['id'],
+        'department_id' => $department['id'],
+        'reference' => 'EMPTY-ORDER-1',
+        'reg_1' => $vehicle['reg'],
+    ]);
+    api_fixtures()->createOrder([
+        'customer_id' => $session['user']['customer_number'],
+        'cashier_id' => $session['user']['id'],
+        'department_id' => $department['id'],
+        'reference' => 'EMPTY-ORDER-2',
+        'reg_1' => $vehicle['reg'],
+    ]);
+
+    $response = api_client()->get('/vehicles?id=' . $vehicle['id'], $session['headers']);
+
+    $response
+        ->assertStatus(200)
+        ->assertEnvelope()
+        ->assertSuccess();
+
+    expect($response->data())->toMatchArray([
+        'id' => $vehicle['id'],
+        'reg' => $vehicle['reg'],
+        'last_order_id' => null,
+    ]);
+});