How to assign Instantiated object through script?

Hello. I have a script called "DestroyGameObject_10s". So that's what I have right now:

     ## DestroyGameObject_10s.cs ##
     public GameObject road;
     public GameObject myCar;
 
     void Start () {
         myCar = GameObject.Find("car");
         road = RoadSpawn.road; // THIS DOESN'T WORK
     }

And the other script called "RoadSpawn.cs"

 void SpawnRoad(){
         spawnedRoad = (GameObject)Instantiate(road, new Vector3(startRoadX + roadXCoordinates, road.transform.position.y, road.transform.position.z), Quaternion.Euler(0,0,0));
         spawnedRoad.AddComponent<DestroyGameObject_10s>();
         roadXCoordinates += 12;
     }

So I want this Instantiated object called spawnedRoad to assign through script. But it doesn't work. Why?

I used RoadSpawn.road; I used RoadSpawn r = new RoadSpawn(); r.road;

But it doesn't work :( Thanks in advance.