How do I make this game properly fullscreen?

import random
from time import sleep

import pygame


class InlineOverdrive:
    def __init__(self):

        pygame.init()
        self.display_width = 600
        self.display_height = 600
        self.black = (0, 0, 0)
        self.white = (255, 255, 255)
        self.clock = pygame.time.Clock()
        self.gameDisplay = None

        self.initialize()

    def initialize(self):

        self.crash = False

        self.carImg = pygame.image.load('.\\img\\Car.png')
        self.car_x_coordinate = (self.display_width * 0.45)
        self.car_y_coordinate = (self.display_height * 0.8)
        self.car_width = 49


        # Background
        self.bgImg = pygame.image.load(".\\img\\Background.png")
        rect = self.bgImg.get_rect ()
        self.bg_x2 = 0
        self.bg_y2 = -600
        self.bg_x1 = 0
        self.bg_y1 = 0

        self.bg_speed = 3
        self.count = 0

    def car(self, car_x_coordinate, car_y_coordinate):
        self.gameDisplay.blit(self.carImg, (car_x_coordinate, car_y_coordinate))

    def racing_window(self):
        self.gameDisplay = pygame.display.set_mode((self.display_width, self.display_height))
        pygame.display.set_caption('Inline Overdrive')
        self.run_car()

    def run_car(self):

        while not self.crash:

            for event in pygame.event.get():
                self.backgroundroad()
                if event.type == pygame.QUIT:
                    self.crash = True
                # print(event)

                if (event.type == pygame.KEYDOWN):
                    if (event.key == pygame.K_LEFT):
                        self.car_x_coordinate -= 50
                        print ("CAR X COORDINATES: %s" % self.car_x_coordinate)
                    if (event.key == pygame.K_RIGHT):
                        self.car_x_coordinate += 50
                        print ("CAR X COORDINATES: %s" % self.car_x_coordinate)
                    print ("x: {x}, y: {y}".format(x=self.car_x_coordinate, y=self.car_y_coordinate))

            self.gameDisplay.fill(self.black)
            self.backgroundroad()
            self.car(self.car_x_coordinate, self.car_y_coordinate)
            self.highscore(self.count)
            self.count += 1
            if (self.count % 100 == 0):
                self.bg_speed += 1

            if self.car_x_coordinate < 100 or self.car_x_coordinate > 360:
                self.crash = True
                self.display_message("You Have Crashed!")

            pygame.display.update()
            self.clock.tick(60)

    def display_message(self, msg):
        font = pygame.font.SysFont("NFS_by_JLTV.ttf", 72, True)
        text = font.render(msg, True, (255, 255, 255))
        self.gameDisplay.blit(text, (400 - text.get_width() // 2, 240 - text.get_height() // 2))
        pygame.display.update()
        self.clock.tick(60)
        sleep(1)
        inline_overdrive.initialize()
        inline_overdrive.racing_window()

    def backgroundroad(self):
        self.gameDisplay.blit(self.bgImg, (self.bg_x1, self.bg_y1))
        self.gameDisplay.blit(self.bgImg, (self.bg_x2, self.bg_y2))
        self.bg_y1 += self.bg_speed
        self.bg_y2 += self.bg_speed

        if self.bg_y1 >= self.display_height:
            self.bg_y1 = 0
        elif self.bg_y2 >= self.display_height:
            self.bg_y2 = 0

    def highscore(self, count):
        font = pygame.font.SysFont("NFS_by_JLTV.ttf", 20)
        text = font.render("SCORE : " + str(count), True, self.white)
        self.gameDisplay.blit(text, (0, 0))


if __name__ == '__main__':
    inline_overdrive = InlineOverdrive()
    inline_overdrive.racing_window()

I want this code to be able to loop the background infinitely as it moves along with the player. The screen currently does not scroll properly. The crash text is also not centered. How can I center it? If I can get my background to work properly, then my game is mostly complete. My car is also off screen for some reason. What needs to be done to make it be on the screen in the background?Image of My Car and Image of My Background