The Tulare County Association of Governments received a $98.4 million federal grant for the upgrades.
The money will be used to add a lane in each direction for over five miles of Highway 99 through the City of Tulare.
The project area runs from south of the Avenue 200 overcrossing to north of the Proseperity Avenue overcrossing.
The money will also be used to rebuild the Paige Avenue interchange.
Local transportation officials say widening this stretch of the highway to six lanes will improve safety and reduce congestion.