Car

using UnityEngine;

public class Car : MonoBehaviour
{
    private const string VERTICAL = "Vertical";
    private const string HORIZONTAL = "Horizontal";

    [SerializeField] private float _speed, _rotationSpeed;
    [SerializeField] private float _maxSpeed, _maxRotationSpeed;

    private Rigidbody2D _rigidbody2D;

    private static float Vertical => Input.GetAxis(VERTICAL);
    private static float Horizontal => Input.GetAxis(HORIZONTAL);

    private void Start() =>
        _rigidbody2D = GetComponent<Rigidbody2D>();

    private void FixedUpdate()
    {
        Acceleration();
        MoveCar();
        StopCar();
    }

    private void Acceleration()
    {
        // набор скорости
        if (_rotationSpeed <= _maxRotationSpeed) _rotationSpeed += Horizontal;
        if (_speed <= _maxSpeed) _speed += Vertical;
    }

    private void MoveCar()
    {
        // управление
        var move = new Vector2(0f, _speed);

        if (_speed != 0)
        {
            _rigidbody2D.AddRelativeForce(move, ForceMode2D.Force);
            _rigidbody2D.AddTorque(-_rotationSpeed);
        }
    }

    private void StopCar()
    {
        // торможение
        if (Vertical == 0)
        {
            if (_speed > 0) _speed -= 2;
            else if (_speed <= 0) _speed = 0;
        }

        if (Horizontal == 0)
        {
            if (_rotationSpeed > 0) _rotationSpeed -= 0.5f;
            else if (_rotationSpeed <= 0) _rotationSpeed = 0;
        }
    }
}