Having a issue with a NullReferenceException

Hello, Im somewhat new to c# I'm working on programming a traffic light when a NullReferenceException is blocking me.

public class TrafficLight : MonoBehaviour {

 [SerializeField]private float greenLight = 5.0f;
 [SerializeField]private float yellowLight = 5.0f;
 [SerializeField]private float redLight =  5.0f; 
 public GameObject CurObject;
 private float timePassed;

 void Start()
 {
     ResetTimeSinceLastRestart ();
     GetComponent<Renderer> ().material.color = Color.gray;
 }

 void Update()
 {
     timePassed += Time.deltaTime; 
 }

 public float GetTime()
 {
     return timePassed;
 }


 public void ResetTimeSinceLastRestart()
 {
     timePassed = 5.0f;
 }
 public float GetRedTime()
 {
     return redLight;
 }

 public float GetYellowTime()
 {
     return yellowLight;
 }

 public float GetGreenTime()
 {
     return greenLight;
 }

}

and my StateMachine Script public class TrafficLightStateMachine : MonoBehaviour {

 private TrafficLight target;
 private TrafficStates curState = TrafficStates.redLight;
 private Dictionary<TrafficStates, Action> fsm = new Dictionary<TrafficStates, Action>();

 enum TrafficStates
 {
     greenLight,
     yellowLight,
     redLight
 }

 void Start () 
 {
     //this accesses the Data Model Script
     GetComponent<TrafficLight> ();
     //this is my dictionary
     fsm.Add (TrafficStates.redLight, new Action (RedState));
     fsm.Add (TrafficStates.yellowLight, new Action (YellowState));
     fsm.Add (TrafficStates.greenLight, new Action (GreenState));
     //This is the default state.
     SetState (TrafficStates.redLight);
 }


 void Update () 
 {
     fsm [curState].Invoke();
 }


 //If the time is greater than timepassed it will transition to the next function: the Yellow light.
 void RedState()
 {
     if (target.GetRedTime() > target.GetTime())
     {
         GameObject greenObj = GameObject.Find("Green Light");

         greenObj.GetComponent<Renderer>().material.color = Color.green;

         SetState (TrafficStates.greenLight);
     }
 }
 //only pay attention to RedState, if i figure out how to fix the red state the rest should follow.
 void YellowState()
 {
     if (target.GetYellowTime() > target.GetTime())
     {
         GameObject RedObj = GameObject.Find("Red Light");

         RedObj.GetComponent<Renderer> ().material.color = Color.red;

         SetState (TrafficStates.redLight);
     }
 }

 void BlinkingYellowState()
 {

 }

 void GreenState()
 {
     if (target.GetGreenTime() > target.GetTime())
     {
         GameObject yellowObj = GameObject.Find("Yellow Light");

         yellowObj.GetComponent<Renderer> ().material.color = Color.yellow;

         SetState (TrafficStates.yellowLight);
     }
 }
 void SetState(TrafficStates newState)
 {
     curState = newState;
 }

}

the errors appear on these two lines: NullReferenceException: Object reference not set to an instance of an object TrafficLightStateMachine.RedState () (at Assets/Lab 1_TrafficLight/Scripts/TrafficLightStateMachine.cs:40) TrafficLightStateMachine.Update () (at Assets/Lab 1_ Traffic Light/Scripts/TrafficLightStateMachine.cs:33)

I'm not sure what the error is and I've been trying for hours.