How make breaks and maximum speed

Hi, I'm trying to make a clone of Hill climb racing. But I don’t know how to make brakes for the car and maximum speed limit, can you suggest me how i can do it? PLEASE HELP ME Thanks in advance

  using System.Collections;
  using System.Collections.Generic;
  using UnityEngine.UI;
  using UnityEngine;
  
  
  public class NewBehaviourScript : MonoBehaviour
  {
      public Rigidbody2D carRigidbody;
      public Rigidbody2D backTire;
      public Rigidbody2D frontTire;
      public float speed = 20;
      public float carTorque = 10;
      private float movement;
      public float maxSpeed = 100f;
      public bool grounded = false;
      public LayerMask map;
      public Transform ring;
      public Text coinsText;
      private int coinsInt = 0;
   
  
  
      // Start is called before the first frame update
      void Start()
      {
  
      }
  
      // Update is called once per frame
      void Update()
      {
          coinsText.text = coinsInt.ToString();
          
          if (grounded == true)
          {
              carTorque = 0;
          }
          else if (grounded == false)
          {
              carTorque = 100;
          }
  
  
          movement = Input.GetAxis("Horizontal");
  
          grounded = Physics2D.OverlapCircle(ring.transform.position, 0.25f, map);
      }
      private void FixedUpdate()
      {
          if (GetComponent<Rigidbody>().velocity.magnitude > maxSpeed)
          {
              GetComponent<Rigidbody>().velocity = GetComponent<Rigidbody>().velocity.normalized * maxSpeed;
          }
          backTire.AddTorque(-movement * speed * Time.fixedDeltaTime);
          frontTire.AddTorque(-movement * speed * Time.fixedDeltaTime);
          carRigidbody.AddTorque(-movement * carTorque * Time.fixedDeltaTime);     
      }
      void OnTriggerEnter2D(Collider2D coins)
      {
          coinsInt++;
          Destroy(coins.gameObject);
      }
  }