sentences:  Subsequently, Istrian municipalities started a public bond to fund the construction of the Učka Tunnel.This construction happened between 1976 and 1981, including the construction of a route section between Matulji and Lupoglav.The "Y shape" formed by the A8 and the A9 routes was originally defined by highway planning documents decided upon in Rijeka and Istria, subsequently incorporated in highway planning documents of the Republic of Croatia in 1988.