The rules that use the vocabulary item "ambulance" are:

<hmmwv>

hmmwv ambulance

<specific_vehicle_type-creatable-sing>

armored personnel carrier ambulance

m113 ambulance

<specific_vehicle_type-not_creatable-sing>

armored personnel carrier ambulance

m113 ambulance

<hmmwv-sing>

hmmwv ambulance

<specific_vehicle_type-sing>

armored personnel carrier ambulance

m113 ambulance

<specific_vehicle_type-not_creatable>

armored personnel carrier ambulance

m113 ambulance