diff --git a/client/src/pages/general-planning.tsx b/client/src/pages/general-planning.tsx
index 5e4b546..bf71929 100644
--- a/client/src/pages/general-planning.tsx
+++ b/client/src/pages/general-planning.tsx
@@ -98,7 +98,7 @@ export default function GeneralPlanning() {
   
   // Form state per assegnazione guardia
   const [selectedGuardId, setSelectedGuardId] = useState<string>("");
-  const [selectedVehicleId, setSelectedVehicleId] = useState<string>("");
+  const [selectedVehicleId, setSelectedVehicleId] = useState<string>("none");
   const [startTime, setStartTime] = useState<string>("06:00");
   const [durationHours, setDurationHours] = useState<number>(8);
   const [consecutiveDays, setConsecutiveDays] = useState<number>(1);
@@ -244,7 +244,7 @@ export default function GeneralPlanning() {
       startTime,
       durationHours,
       consecutiveDays,
-      ...(selectedVehicleId && { vehicleId: selectedVehicleId }),
+      ...(selectedVehicleId && selectedVehicleId !== "none" && { vehicleId: selectedVehicleId }),
     });
   };
 
@@ -738,7 +738,7 @@ export default function GeneralPlanning() {
                           <SelectValue placeholder="Nessun veicolo" />
                         </SelectTrigger>
                         <SelectContent>
-                          <SelectItem value="">Nessun veicolo</SelectItem>
+                          <SelectItem value="none">Nessun veicolo</SelectItem>
                           {availableVehicles && availableVehicles.length > 0 ? (
                             availableVehicles.map((vehicle) => (
                               <SelectItem key={vehicle.id} value={vehicle.id}>