Variable seems to reset itseld

#import menu_functions
from menu_functions import game_menu,modification_menu,changing_wheels_menu,changing_passenger_bay_menu,info_menu,menu_choices

traction_type=0
passengers=0

#The menu choices_menu_file is where i made the menus link to one another

game=True
global game
while(game==True):
    menu_choices()
    print("Game is currently: ",game)

def game_menu():
    global game
    global choice
    choice = ''
    print('MENU')
    print('====')
    print('1] Play game')
    print('2] Modify robot')
    print('3] Information Menu')
    print('4] Exit game')
    while choice not in ['1','2','3','4']:
        choice = input('Make your choice')

def modification_menu ():
    global game
    global choice
    choice = ''
    print ('MODIFICATION MENU')
    print ('=================')
    print ('1] Change Wheels')
    print ('2] Change Passenger Bay')
    print ('3] Back to Main Menu')
    while choice not in ['1','2','3']:
        choice = input('make your choice')

def changing_wheels_menu ():
    global game
    global choice
    choice = ''
    print ('CHANGING WHEELS')
    print ('===============')
    print ('1] Change to Wooden Wheel')
    print ('2] Change to Skis')
    print ('3] Change to Tracks')
    print ('4] Exit to Modification Menu')
    while choice not in ['1','2','3']:
        choice = input('make your choice')


def changing_passenger_bay_menu ():
    global game
    global choice
    choice = ''
    print ('CHANGING PASSENGER BAY')
    print ('===============')
    print ('1] Change to a Large bay')
    print ('2] Change to a Medium bay')
    print ('3] Change to a Small bay')
    print ('4] Exit to Modification Menu')
    while choice not in ['1','2','3']:
        choice = input('Make your choice')

def info_menu ():
    global game
    global choice
    choice = ''
    print ('INFORMATION MENU')
    print ('================')
    print ('WHEELS')
    print ('======')
    print ('Wooden Wheels:')
    print ('costs 1 unit of power on grassland')
    print ('costs 2 unit of power on rocks')
    print ('costs 3 unit of power on ice')
    print ('Tracks:')
    print ('costs 3 unit of power on grassland')
    print ('costs 3 unit of power on rocks')
    print ('costs 3 unit of power on ice')
    print ('Skis:')
    print ('costs 3 unit of power on grassland')
    print ('costs 3 unit of power on rocks')
    print ('costs 1 unit of power on ice')
    print ('==================================')
    print ('PASSENGER BAY')
    print ('=============')
    print ('large: costs 2 unit of power and can hold 3 passengers')
    print ('medium: costs 1 unit of power and can hold 2 passengers')
    print ('small: costs 0 unit of power and can hold 1 passenger')

def menu_choices():
    global game
    global choice
    game_menu()
    if choice=="1":
        print ('coming soon!!!')
    elif choice=="2":
        modification_menu()
        if choice=="1":
            changing_wheels_menu()
            if choice=="1":
                print ('you chose wheels!')
                traction_type="1"
            elif choice=="2":
                print ('you chose skis!')
                traction_type="2"
            elif choice=="3":
                print ('you chose tracks!')
                traction_type="3"
        elif choice=="2":
            changing_passenger_bay_menu()
            if choice=="1":
                print ('you chose a Large bay!')
                passengers="3"
            elif choice=="2":
                print ('you chose a Medium bay!')
                passengers="2"
        elif choice=="3":
            print ('you chose a Small bay!')
            passengers="1"
    elif choice=="3":
        info_menu()
    elif choice=="4":
        game=False
        print("Game is currently: ",game)
        print('Exiting')

$ python
Python 2.7.3 (default, Sep 26 2012, 21:51:14) 
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> global a
>>> a = 'a in __main__ module'
>>> import p
>>> import q
>>> print(a)
a in __main__ module
>>> print(p.a)
1
>>> print (q.a)
a in q.py
>>> 

import menu_functions
from menu_functions import game_menu,modification_menu,changing_wheels_menu,changing_passenger_bay_menu,info_menu,menu_choices

traction_type=0
passengers=0

#The menu choices_menu_file is where i made the menus link to one another

while(menu_functions.game):
    menu_choices()
    print("Game is currently: ",menu_functions.game)