#imports
import random
import pygame
import sys
#import stater
#clock
clock=pygame.time.Clock()
fps=70
#screen
pygame.init()
screen=pygame.display.set_mode((500,670))
pygame.display.set_caption("cross the road")
while True:
        for eve in pygame.event.get():
            if eve.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

code1 simple setup for pygame

#imports
import random
import pygame
import sys
#import stater
#clock
clock=pygame.time.Clock()
fps=70
#screen
pygame.init()
screen=pygame.display.set_mode((500,670))
pygame.display.set_caption("cross the road")
#class for road
#       |
#       v
class road(pygame.sprite.Sprite):
    def __init__(self,pos_x,pos_y,speed):
        super().__init__()
        self.posy=pos_y
        self.posx=pos_x
        self.speed=speed
        self.rand=0
        self.roads=[]
        self.roads.append(pygame.image.load("images/road_0.png").convert())
        self.image=self.roads[self.rand]
        self.rect=self.image.get_rect(bottomleft=(self.posx,self.posy))        
    def update(self):
        self.posy+=self.speed
        if self.posy>=670+150:
            self.rand=0
            self.image=self.roads[self.rand]
            self.posy=-300

        self.rect=self.image.get_rect(bottomleft=(self.posx,self.posy))
while True:
        for eve in pygame.event.get():
            if eve.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

Added road class to create road

#imports
import random
import pygame
import sys
#import stater
#clock
clock=pygame.time.Clock()
fps=70
#screen
pygame.init()
screen=pygame.display.set_mode((500,670))
pygame.display.set_caption("cross the road")
#pos
posx=234
posy=600
r1y=-375
r2y=0
r3y=375
rs=0.75
#class for road
#       |
#       v
class road(pygame.sprite.Sprite):
    def __init__(self,pos_x,pos_y,speed):
        super().__init__()
        self.posy=pos_y
        self.posx=pos_x
        self.speed=speed
        self.rand=0
        self.roads=[]
        self.roads.append(pygame.image.load("images/road_0.png").convert())
        self.image=self.roads[self.rand]
        self.rect=self.image.get_rect(bottomleft=(self.posx,self.posy))        
    def update(self):
        self.posy+=self.speed
        if self.posy>=670+150:
            self.rand=0
            self.image=self.roads[self.rand]
            self.posy=-300

        self.rect=self.image.get_rect(bottomleft=(self.posx,self.posy))

while True:
        for eve in pygame.event.get():
            if eve.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

Added important variable

#imports
import random
import pygame
import sys
#import stater
#clock
clock=pygame.time.Clock()
fps=70
#screen
pygame.init()
screen=pygame.display.set_mode((500,670))
pygame.display.set_caption("cross the road")
#pos
posx=234
posy=600
r1y=-375
r2y=0
r3y=375
rs=0.75
#class for road
#       |
#       v
class road(pygame.sprite.Sprite):
    def __init__(self,pos_x,pos_y,speed):
        super().__init__()
        self.posy=pos_y
        self.posx=pos_x
        self.speed=speed
        self.rand=0
        self.roads=[]
        self.roads.append(pygame.image.load("images/road_0.png").convert())
        self.image=self.roads[self.rand]
        self.rect=self.image.get_rect(bottomleft=(self.posx,self.posy))        
    def update(self):
        self.posy+=self.speed
        if self.posy>=670+150:
            self.rand=0
            self.image=self.roads[self.rand]
            self.posy=-300

        self.rect=self.image.get_rect(bottomleft=(self.posx,self.posy))

#group of sprite
sprite=pygame.sprite.Group()
sprite_car=pygame.sprite.Group()
#road1
road1=road(0,r1y,rs)
sprite.add(road1)

#road2
road2=road(0,r2y,rs)
sprite.add(road2)

#road3
road3=road(0,r3y,rs)
sprite.add(road3)
while True:
        screen.fill((0,145,0))
        for eve in pygame.event.get():
            if eve.type == pygame.QUIT:
                pygame.quit()
                sys.exit()
        rs+=0.01
        sprite.draw(screen)
        sprite.update()
        pygame.display.update()
        clock.tick(fps)

created and added road class instance to group and drawn them