The US Department of Transportation has approved $386m to the North Carolina Turnpike Authority (NCTA) to build two brand new sections of the Triangle Expressway in the Raleigh-Durham area of the state.

NCTA is expected to sell more than $600m in bonds in order to raise the remaining amount required for the $1.1bn Triangle Expressway project.

The fund will be utilised to construct Triangle Expressway constituting 18 miles of roadway, linking the key interstates and state routes in the region.

The Triangle Expressway mainly includes a new Triangle Parkway extending 3.4 miles north from NC 540, the new Western Wake Freeway continuing NC 540 south for an additional 12.6 miles and the existing North Wake Freeway extending NC 540 south for 2.8 miles.

The new sections will provide access to the Research Triangle Park, one of the largest science parks in North America and home to about 160 companies employing more than 40,000 high-tech workers.

The three adjacent sections will improve access to I-40 and downtown Raleigh.