What units are used for the axis. (Speed per Second Script included!) ;-)

So I wrote this simple speed script (feel free to use it if you'd like). My question is what am I calculating is the x-axis in meters therefor m/s. If it helps my vehicle is moving at a moderate speed and am averaging around 30 speed per second.

So this is a pretty crude way of detecting speed, but it is accurate enough for what I need. There are a few limitations,..

1) Only going to work for a 2D game and ignores values of why, you could use the same idea with vector3's i suppose.

2) If you do not want negative values for speed you should use math.Abs when calculating.

 public class SpeedDetection : MonoBehaviour {
 
     GameObject obj;
 
 
     float realPos = 0;
     float currentPos = 0;
     float lastPos = 0;
     
     public float speed;
 
     // Use this for initialization
     void Start () {
 
         obj = GameObject.Find ("objName");
 
         InvokeRepeating ("Speed", 1 , Time.deltaTime * 60);
     
     }
 
     void Speed()
     {
         currentPos = realPos;
 
         speed = currentPos - lastPos;
 
         lastPos = currentPos;
 
 
     }
     
     // Update is called once per frame
     void Update () {
 
         realPos = forkLift.transform.position.x;
 
     
     }
 }