Unity 3D Navesh Agent Control - step 1

using UnityEngine;
using System.Collections;

public class AgentControl : MonoBehaviour {

    public Transform target;
    NavMeshAgent agent;
    float originalSpeed;

    // Use this for initialization
    void Start () {
        agent = GetComponent<NavMeshAgent>();
        originalSpeed = agent.speed;
    }

    // Update is called once per frame
    void Update () {

        int mask = 1 << NavMesh.GetNavMeshLayerFromName("No Running");

        NavMeshHit navHit;
        agent.SamplePathPosition (-1, 0, out navHit);


        if ( (navHit.mask & mask) != 0)
        {
            agent.speed = originalSpeed * 0.3f;

        } else {
            agent.speed = originalSpeed;
        }

        agent.SetDestination( target.position );
    }
}