diff --git a/include/VehicleData.h b/include/VehicleData.h
index f26392b..7aac080 100644
--- a/include/VehicleData.h
+++ b/include/VehicleData.h
@@ -11,13 +11,13 @@ public:
     [[nodiscard]] int ID() const { return mID; }
 
     [[nodiscard]] std::string Data() const { return mData; }
-    void SetData(const std::string& Data) { mData = Data; }
+    void SetData(const std::string& Data) const { mData = Data; }
 
     bool operator==(const TVehicleData& v) const { return mID == v.mID; }
 
 private:
     int mID { -1 };
-    std::string mData;
+    mutable std::string mData;
 };
 
 namespace std {
diff --git a/src/Client.cpp b/src/Client.cpp
index 4283cb4..d9636f9 100644
--- a/src/Client.cpp
+++ b/src/Client.cpp
@@ -54,7 +54,7 @@ std::string TClient::GetCarData(int Ident) {
 void TClient::SetCarData(int Ident, const std::string& Data) {
     for (auto& v : mVehicleData) {
         if (v.ID() == Ident) {
-            v.Data() = Data;
+            v.SetData(Data);
             return;
         }
     }