'Gare routière' is French for bus station: the one at Bertrange-Strassen station.
The bus station is next to Bertrange-Strassen railway station, which also serves Strassen to the north. The station lies on the CFL line from Luxembourg via Kleinbettingen to Arlon; its first building went up in 1858 and the old station was demolished in 1976 when the whole site was modernised.