The central portion of a road for high speed vehicle is known as:

Explanation:

Expressway or Motorway:

• The central portion of the road has been specially built (designed) for high-speed vehicles (or fast travel over long distances).

Additional Information

Highways:

Highways classified into two categories

1. National Highways (NH):

• National highways are main highways running through the length and breadth of India connecting major ports, foreign highways, the capital of large states, and large Industrial and tourist centers including roads required for strategic movements for the defense of India.

2. State Highways (SH):

• State highways are arterial roads of a state, connecting the national highways of adjacent states, district headquarters, and important cities within the state.

Urban Roads:

• District Roads (DR) or Major District Roads (MDR) come under this category.

Semi-Urban Roads:

The following roads come under the category of semi-urban roads.

• Other District Roads (ODR): Other district roads are roads serving the rural areas of the population and providing them with outlets to market centers, taluk headquarters, or other main roads.
• Village Road (VR): Village roads are connecting villages or groups of villages.