The "Américo Vespucio Oriente" Concession (AVO 1) is part of ambitious program, promoted by the Chilean Ministry of Public Works, to close this Ring Road to highway standard in Santiago de Chile. The project integrates this 8,278 m highway with three lanes in each direction, of which 7,678 m are underground, in a dense urban area of the city. The underground works combines 3 main construction methods: SEM and NATM tunnel: La Pirámide and Mapocho Branch (2,100 + 415 m).Cut & Cover tunnel: 2,891 m in a pile trench with two subway platform levels. "Hybrid" tunnel: 2,687 m between Apoquindo and Tobalaba. The construction works began in November 2017 and its completion was done in July 2022, with a inal budget of 900 MUSD. Based on the set of conditioning factors, a highly innovative hybrid tunnel section solution was designed to the it the tunnel layout under an existing boulevard, as well as each of the seven existing connections with exit/enter branches. The hybrid tunnel enables two roads overlapped with three lanes each. Level -1 platform is resolved by means of a NATM tunnel, while Level -2 has been constructed as a conventional trench-type structure using 1.00x1.00 m handmade piles with different spacings and a minimum embedment of 3.5 m, which are braced at their head by a post-tensioned slab between both levels. The gap between piles is reinforced by means of a lining wall. The hybrid tunnel has crossed below two existing underground parkings as well as under metro line 1. For that purpose, an improvement using jet-grouting from the deepest parking level was done. The paper describes the main design facts as well as the experiences during its construction.