This is the 775th most frequent Polish word.
budowę
The Polish word "budowę" means "construction" or "building" (accusative form of "budowa").
Here, 'budowę' (used as 'budowie') is part of an expression in the locative case, referring to the domain of expertise in constructing roads.
Ta firma specjalizuje się w budowie dróg.
This company specializes in road construction.
In this case, 'budowę' (used as 'budowy') also functions as a noun, here in the genitive case, referring to the time or context of construction activity.
Podczas budowy odkryto stare artefakty.
Old artifacts were discovered during the construction.
In this sentence, 'budowę' is used as a noun in the accusative case, referring to the process of constructing a physical structure.