diff --git a/services/nginx/app/routes/vehiclesRoute.php b/services/nginx/app/routes/vehiclesRoute.php
index 94084d96..43140327 100644
--- a/services/nginx/app/routes/vehiclesRoute.php
+++ b/services/nginx/app/routes/vehiclesRoute.php
@@ -734,13 +734,29 @@ class vehiclesRoute
             $search = (string)self::getParameter('search');
             self::requireMinLength('search', 1);
             self::requireMaxLength('search', 12);
+            $department = null;
+            // If department is set, validate it
+            if (self::isParametersSet(['department'])) {
+                $department = (int)self::getParameter('department');
+                self::requireType($department, self::type_int());
+                self::requireMinValue($department, 1);
+                self::requireMaxValue($department, 999999);
+                // Check if the department exists
+                $department_o = new departments_o();
+                $department_o->select($department);
+                if (!$department_o->exists()) {
+                    $response->error('Department not found', 404);
+                }
+                self::requireDepartmentAccess($department);
+            }
             // Strip the search term of whitespace
             $search = preg_replace('/\s+/', '', $search);
             /** Get the different lists of registration numbers */
             $options = ['limit' => 10];
+            $booked_filters = [...($department ? ['department' => $department] : [])];
             $verified_regs = self::getVerifiedRegs($search, $options);
             $known_regs = self::getKnownRegs($search, $options);
-            $booked_regs = self::getBookedRegs($search, $options);
+            $booked_regs = self::getBookedRegs($search, $options, $booked_filters);
             $unknown_regs = array_filter(array_unique(array_merge([...self::getUnknownRegs($search, $options), $search]))); // Add the search term as the first item, to ensure it is included in the results
             /**
              * Prevent overlaps between the lists
@@ -930,7 +946,7 @@ class vehiclesRoute
         }, $results);
     }
 
-    private static function getBookedRegs(string $search, array $options = ['limit' => null]): array
+    private static function getBookedRegs(string $search, array $options = ['limit' => null], ?array $filters = []): array
     {
         $bookings_o = new order_bookings_o();
         /**
@@ -957,6 +973,7 @@ class vehiclesRoute
             [
                 'reg_1' => $search,
                 'order_id' => null,
+                ...$filters
             ],
             ['reg_1'],
             $options
@@ -965,6 +982,7 @@ class vehiclesRoute
             [
                 'reg_2' => $search,
                 'order_id' => null,
+                ...$filters
             ],
             ['reg_2'],
             $options