Furthermore, to supply the people, for their daily needs, requires the transportation of goods between production and consumption centers, this eminent role, has also a vital value and importance.
All the connection links, including road, railway, waterway, and airway take part for passengers travel and transporation of goods, however, in spite of a great progress in the other three modes of transportation, still "Road" plays an special and strategic role in transportation, this, arises partly, from the flexibility of road transportation.
Owing to the roles, functions and effects of "Road" on providing for social, cultural, technologival, economics and defensive needs, the length of highway grid is a suitable criterion to measure the development level of every country.
With a lot of experiences acquired during about a quarter of century, IRDO, is the largest constrauction contractor, for the Ministry of Road and Transportation, that since its establishment, has undertaken diffrent works including construction of road,railway tunnel, bridge, airfield, runway, ground levelling paving and large warehouse.
At a general glance, IRDO's important and main activities, has been included the following item:

A: Two-lane highway, first and second class, in a total length of 4000km.

B: Bridges and culverts in a number of 400 and 3700, respectively.

C: Tunnel, in a total length of 20 km.

D: Freeway and multi-lane highway, in total length of 500km.

E: Railway substructure, in a total length of 400km.

F: Airfield and runway for 10 airports.