Дорожное движение

using System.Collections.Generic;
using UnityEngine;

public class Crossing : MonoBehaviour
{
    [SerializeField] private GameObject carPrefab;
    [SerializeField] private float[] lanes;
    [SerializeField] private float spawnEvery = 1f;
    [SerializeField] private float carSpeed = 5f;

    private Vector3 start;

    void Start()
    {
        start = transform.position;
    }

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.UpArrow))
        {
            transform.position += new Vector3(0f, 0f, 2f);
        }
        if (Input.GetKeyDown(KeyCode.DownArrow) && transform.position.z > start.z)
        {
            transform.position -= new Vector3(0f, 0f, 2f);
        }
        if (transform.position.z >= 4f)
        {
            Debug.Log("You made it!");
            enabled = false;
            return;
        }

        // Машины: в следующем уроке.
    }
}