With the massive increase in traffic that has ensued from the Kingdom's industrial and agricultural development, it has been necessary to upgrade many of the inter-city roads to expressways, with anything up to eight lanes for traffic. The cities too have become congested by the growth in traffic and a number of cities now enjoy the benefits of modern ring-roads which serve to speed vehicles on their way and reduce congestion and pollution in city centres. A further development is the construction of networks of over- and under-passes within the cities which again serve to facilitate driving in city centres.

Civil aviation occupies a special place in any account of the Kingdom's transportation systems. In 1945, Franklin D Roosevelt, President of the United States of America, presented a DC-3 Dakota to the late King Abdul Aziz. Quick to realize the contribution that air travel could make to the development of the Kingdom, the King promptly ordered two more planes.

These three planes formed the embryo of what has grown into Saudi Arabian Airlines, the Kingdom's flag carrier, and now one of the world's leading airlines - an airline which has in its fleet today more than 100 aircraft (including a number of Boeing 747s, Boeing 777s and Airbuses) and which, in early 1999, had 24 local and 52 international stations and was transporting 12.7 million passengers and 253 million kilogram of cargo. The airline continues to expand to meet increasing demand.

Railways remain the least developed means of transportation in the Kingdom. There are vast distances to cover, in often adverse environmental conditions, and it was inevitable that airline services seem to be a more practical mode of transportation to a country undertaking a major development program in the second half of the twentieth century.

The Kingdom's railways currently consists primarily of a single track, standard-gauge line, running for 570 kilometers from Riyadh to Dammam in the eastern region. This line which was opened in 1951, passes through Dhahran, Abqaiq, Hofuf, Harad and al-Kharj and has benefited from substantial renovation in recent years. An additional line joining Hofuf with Riyadh was opened in 1985.

The Kingdom's railways are managed by the Saudi Arabian Railway Corporation (now the Saudi Railways Organization), established in 1976 as an independent public utility, governed by a board of directors.

Railways:
total: 1,392 km
standard gauge: 1,392 km 1.435-m gauge (with branch lines and sidings) (2004)

Highways:
total: 152,044 km
paved: 45,461 km
unpaved: 106,583 km (2000)

Pipelines:
condensate 212 km; gas 1,780 km; liquid petroleum gas 1,191 km; oil 5,068 km; refined products 1,162 km (2004))

Ports and harbors:
Dammam, Al Jubail, Jeddah, Yanbu' al Sinaiyah

Merchant marine:
total: 64 ships (1,000 GRT or over) 1,306,706 GRT/1,963,191 DWT
by type: cargo 5, chemical tanker 12, container 4, passenger/cargo 8, petroleum tanker 23, refrigerated cargo 3, roll on/roll off 9
foreign-owned: 14 (Egypt 2, Hong Kong 1, Kuwait 5, Singapore 1, Sudan 1, UAE 1, United Kingdom 3)
registered in other countries: 54 (2005)

Airports:
201 (2004 est.)

Airports - with paved runways:
total: 72
2,438 to 3,047 m: 13
1,524 to 2,437 m: 23
914 to 1,523 m: 2

Airports - with unpaved runways:
total: 129
over 3047 m: 1
2,438 to 3,047 m: 5
1,524 to 2,437 m: 72
914 to 1,523 m: 39
under 914 m: 12 (2004 est.)

Heliports:
5 (2004 est.)