My indents for my loops look strange, is this normal? (python 2)

I'm trying to create loops when certain conditions are met and so far it works but when I try to create more conditions I have to indent them even more in order to get my program to work.

def terrain(surface):
    surface = raw_input("What surface will you be driving on? ")
    while surface != "ice" and surface != "concrete" and surface != "soil" and surface != "asphalt" :
        surface = raw_input("Surface not valid. Please enter a valid surface: ")
    if surface == "ice":
                u = raw_input("what is the velocity of the car in meters per second? ")
                u = int(u)
                while int(u) < 0:
                    u = raw_input("Velocity must be a positive integer: ")
                                while int(u) == 0:
                                    u = raw_input("Velocty must be a number greater than zero: ")
                        while int(u) > 72:
                                                                u = raw_input("This vehicle cannot reach this speed: ")
                a = raw_input("How quickly is the vehicle decelerating? ")
                a = int(a)
                while int(a) > 0:
                    a = raw_input("Deceleration cannot be a positive integer: ")
                else: 
                        s1 = u**2
                        s2 = 2*.08*9.8
                    s = s1/s2
                    print "This is how far the vehicle will travel on ice: "
                    print ("The vehicle will travel %i meters before coming to a complete stop" % (s))
terrain("ice")

I just want to be able to create more loops without the wild indents