private Level[] levels;

[System.Serializable]
public class Level
{
    public int levelNo;
    public Road[] roads;
}

[System.Serializable]
public class Road
{
    public int roadNo;  //0-1-2   leftmost is 0
    public string[] roadNames;
    public float[] roadYOffsets;
}

private void readJson()
{
    jsonPath = Path.Combine(Application.streamingAssetsPath , "LevelConfig.json");
    string json = File.ReadAllText(jsonPath);
    levels = JsonHelper.FromJson<Level>(json);
    int i = 0;
    Debug.Log(levels[i].roads.Length);
    for(i=0;i<levels[0].roads.Length;i++)
    {
        Debug.Log(levels[0].roads[i].roadNo);
    }
    while(i < levels.Length)
    {
        levels[i].roads = JsonHelper.FromJson<Road>(json);
        i++;
    }
    i = 0;
    int j;
    while (i<levels.Length)
    {
        j=0;
        while (j < levels[i].roads.Length)
        {
            int k = 0;
            while (k < levels[i].roads[j].roadNames.Length)
            {
                Debug.Log(levels[i].levelNo + " roadno" + levels[i].roads[j].roadNo + " roadtype" + levels[i].roads[j].roadNames[k] + " offsets" + levels[i].roads[j].roadYOffsets[k]);
                k++;
            }
            j++;
        }
        i++;
    }
}


public static class JsonHelper
{
    public static T[] FromJson<T>(string json)
    {
        Wrapper<T> wrapper = JsonUtility.FromJson<Wrapper<T>>(json);
        return wrapper.Items;
    }

    public static string ToJson<T>(T[] array)
    {
        Wrapper<T> wrapper = new Wrapper<T>();
        wrapper.Items = array;
        return JsonUtility.ToJson(wrapper);
    }

    public static string ToJson<T>(T[] array, bool prettyPrint)
    {
        Wrapper<T> wrapper = new Wrapper<T>();
        wrapper.Items = array;
        return JsonUtility.ToJson(wrapper, prettyPrint);
    }

    [Serializable]
    private class Wrapper<T>
    {
        public T[] Items;
    }
}



{
    "Levels":
    [
        {
            "levelNo": 1,
            "roads":
            [
                {
                    "roadNo": 0,
                    "roadNames": [ "DefaultRoad", "DefaultRoad", "DefaultRoad", "DefaultRoad" ],
                    "roadYOffsets": [ 0, 1, -1, 0 ]
                }
            ]
        }
    ]
}