Checkpoint System

Hello! I put the script in all checkpoints. When the car passes the first checkpoint, it will go straight to the first one or the last one. Can anyone help me?

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class CheckpointScript : MonoBehaviour
 {
     public GameObject LapCompleteTrig;
     public GameObject Checkpoint1;
     public GameObject Checkpoint2;
     public GameObject Checkpoint3;
     public int CheckpointTracker;
     
     //When the car passes the first checkpoint, the checkpoint goes straight to the first one or the last one.
     //After the car passes the last checkpoint, the checkpoint stays in place.
     void Update()
     {
         if (CheckpointTracker == 0)
         {
             LapCompleteTrig.SetActive(false);
             Checkpoint1.SetActive(true);
             Checkpoint2.SetActive(false);
             Checkpoint3.SetActive(false);
         }
 
         if (CheckpointTracker == 1)
         {
             LapCompleteTrig.SetActive(false);
             Checkpoint1.SetActive(false);
             Checkpoint2.SetActive(true);
             Checkpoint3.SetActive(false);
         }
 
         if (CheckpointTracker == 2)
         {
             LapCompleteTrig.SetActive(false);
             Checkpoint1.SetActive(false);
             Checkpoint2.SetActive(false);
             Checkpoint3.SetActive(true);
         }
 
         if (CheckpointTracker == 3)
         {
             LapCompleteTrig.SetActive(true);
             Checkpoint1.SetActive(false);
             Checkpoint2.SetActive(false);
             Checkpoint3.SetActive(false);
         }
     }
 
     void OnTriggerEnter(Collider other)
     {
         if (other.gameObject.tag == "Player")
         {
             CheckpointTracker += 1;
             if (CheckpointTracker == 4)
             {
                 CheckpointTracker = 0;
             }
         }
     }
 }