Adding collisions to a custom character controller?

Alright, so I’m currently making a game where players control cars (3rd person view), but I can’t seem to get players to collide with object colliders, let alone other players. I have written a custom character controller and apparently do not know how to implement collisions with the new script.

Here is my code:

using UnityEngine;
using System.Collections;

public class CarController : MonoBehaviour {
	private float speed = 9.0f;
	private float boostSpeed = 1.5f;
	private float rollRate = 20.0f;
	private float elevatorRate = 3.0f;
	private float rudderRate = 100.0f;

	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
		if (Input.GetButton ("Forward"))
		{
			transform.Translate(-1.0f * speed * Time.deltaTime, 0, 0); //the thrust forward
		}

		if (Input.GetButton ("Backward"))
		{
			transform.Translate(speed * Time.deltaTime, 0, 0); //the thrust forward
		}

		if (Input.GetButton ("Boost"))
		{
			transform.Translate(-1.0f * boostSpeed * speed * Time.deltaTime, 0, 0);
		}

		if (Input.GetButton ("Rollright"))
		{
			transform.Rotate(rollRate * Time.deltaTime, 0, 0);
		}
		else if (Input.GetButton ("Rollleft"))
		{
			transform.Rotate(rollRate * -1.0f * Time.deltaTime, 0, 0);
		}
		if (Input.GetButton ("Rise"))
		{
			transform.Translate(0, elevatorRate * Time.deltaTime, 0);
		}
		else if (Input.GetButton ("Dive"))
		{
			transform.Translate(0, elevatorRate * -1.0f * Time.deltaTime, 0);
		}
		if (Input.GetButton ("Rudderright"))
		{
			transform.Rotate(0, rudderRate * Time.deltaTime, -.07f * Time.deltaTime);
		}
		else if (Input.GetButton ("Rudderleft"))
		{
			transform.Rotate(0, rudderRate * -1.0f * Time.deltaTime, .07f * Time.deltaTime);
		}
	}
}

I have colliders and a Rigidbody attached to my player prefab, with the Rigidbody set to “Is Kinematic”. Any help would be appreciated!

You need to actually implement the collision detection.
You do this by having the OnCollisionEnter callback in your script or to separate behaviour create a new separate script on your car eg. CarCollision.

For example, you could also add an AudioSource component to your car, set a crash sound to the AudioSource, add the following script to your car & it will play the crash sound when the car collides with something.

using UnityEngine;
using System.Collections;

public class CarCollision : MonoBehaviour {
	AudioSource audio;
	
	void Awake() {
		audio = GetComponent<AudioSource>();
	}
	
    void OnCollisionEnter(Collision collision) {
        if (collision.relativeVelocity.magnitude > 2)
            audio.Play();
    
    }
}