▁( S her idan ▁Bou lev ard ) ▁and ▁the ▁Trib or ough ▁Bridge . ▁ ▁North ▁of ▁the ▁inter change ▁the ▁road ▁ve ers ▁to ▁the ▁n ortheast ▁slightly ▁and ▁cross es ▁the ▁rail road ▁tracks ▁of ▁Am tra k ' s ▁N ortheast ▁Cor rid or ▁line . ▁At ▁East ▁ 1 8 0 th ▁Street , ▁the ▁linear ▁park ▁ends ▁tempor arily . ▁The ▁road ▁becomes ▁elev ated ▁to ▁cross ▁the ▁East ▁ 1 8 0 th ▁Street ▁Y ard ▁along ▁the ▁New ▁York ▁City ▁Sub way ' s ▁I RT ▁White ▁Pla ins ▁Road ▁Line , ▁which ▁car ries ▁the ▁, ▁as ▁well ▁as ▁the ▁former ▁New ▁York , ▁West chester ▁and ▁Boston ▁Railway . ▁After ▁crossing ▁the ▁yard , ▁wood ed ▁surr ound ings ▁res ume ▁as ▁the ▁park way ▁follows ▁the ▁eastern ▁edge ▁of ▁the ▁Bron x ▁Z oo ▁in ▁the ▁Bron x ▁Park ▁neighborhood ▁and ▁the ▁Bron x ▁River , ▁which ▁gives ▁the ▁road ▁its ▁name , ▁begins ▁to ▁follow ▁it ▁on ▁the ▁west . ▁On ▁the ▁north bound ▁side , ▁as ▁it ▁enters ▁the ▁park , ▁is ▁an ▁un number ed ▁exit ▁allowing ▁author ized ▁vehicles ▁( like ▁those ▁of ▁people ▁working ▁at ▁the ▁NY C ▁Park s ▁Department ) ▁access ▁to ▁local ▁streets ▁via ▁Bir ch all ▁Avenue . ▁ ▁A ▁quarter - mile ▁to ▁the ▁north ▁is ▁the ▁main ▁exit ▁for ▁the ▁zoo ▁at ▁Boston ▁Road , ▁with ▁access ▁to ▁Boston ▁Road ▁( U . S . ▁Route   1 ▁or ▁US  