I talked about this a bit with my Ob, and she said ambos (generally) would rather you had the baby at home or in hospital but not in transit. So if the ambos arrive and you really think it is close (or you tell them you are ) you may have a good argument for staying put for the time being.

Another thing to consider was my first baby was born very quickly and she got a bit stressed by it and needed some oxygen and other help as soon as she was born. Obviously if you plan a home birth you have an attendant to look after this, but if it is unplanned or on the side of the road that help and oxygen is not available, so having ambos near by might not be all that bad.

Good luck! I've always said if I do end up having a third baby I will be the women on the news who has her baby on the side of the road, so I understand your fears!