The two-lane Santa Ana-Belén highway will be widened to five lanes, the Consejo de Nacional de Vialidad said Monday.
The work is being supported by the Asociación Consejo de Desarrollo Inmobiliario, a real estate advocacy organization, which is putting up $2 million.
The entire job will be $34 million, said the Consejo.
The job includes replacing four bridges, including one of 180 meters (about 590 feet) over the Río Virilla.
The work is scheduled to begin in January with the relocation of public utilities in advance of road work.
The Consejo will finance its share of the cost.
The distance is two kilometers, about 1.24 miles. This section of roadway carried about 31,500 vehicles a day.