class Class1:

    def __init__(self):
        self.canvas = tkinter.Canvas(width=500, height=500, bg="white")
        self.canvas.pack()
        number = x
        self.create_npc(number)
        ...

    def create_npc(self):
        for i in range(number):
            self.canvas.after(3000)
            self.npc = NPC(self)

    ...

class NPC:

    def __init__(self, class1):
        self.main = class1
        self.place_npc()
        self.move_npc()

    def place_npc(self):
        self.object_npc = self.main.canvas.create_image(some_x, some_y, image=self.main.cars['self.car_image_1']) #there is a dict with all car images

    def move_npc(self):
        while True:
            self.main.canvas.move(self.object, 10, 0)