Transport in Saudi Arabia is facilitated through a relatively young system of roads, railways and seaways. Most of the network started construction after the discovery of oil in the Eastern Province in 1952, with the notable exception of Highway 40, which was built to connect the capital Riyadh to the economically productive Eastern Province, and later to the Islamic holy city of Mecca and the port city of Jeddah. With the economic growth of the 1970s, the Kingdom of Saudi Arabia has initiated many infrastructure development projects across the country, and the extensive development of the transportation network has followed suit in support of various economic developments. History and overview Road network The roads of Saudi Arabia gradually became the defining feature of the kingdom's transport system as the main population centres are not only scattered all over the country but also because they faced a major challenge from the geography of the country itself; separated by deserts, valleys and mountains, among other landforms. Due to this, a reliable road network became more important and essential than other modes of transport in the kingdom. Saudi Arabia had encouraged road transport in the past by maintaining one of the lowest petrol prices in the world. Despite raising prices in 2018, it is worth noting that due to limited alternative passenger transport options in the country, the gasoline fuel demand is relatively inelastic to its prices; light-duty vehicles dominate the passenger transport landscape. Buses and other public transport options are limited, and walking or bicycles are hindered by the urban landscapes and harsh weather in most regions of the country. The development of the Saudi road network can be divided into two major phases; i.e. the expansion of the modern road network from 1938 to 1970, preceding the initial development plans conceived by the Ministry of Transport, and the development and expansion after the introduction of the plans (after 1970). The two stages, pre-national planning and postnational planning, relate to the historical circumstances of the economic, political and social demands of the kingdom. The activity during the second stage greatly exceeds that during the first owing to the existence of coordinated plans, high investment and concentration of effort. Rail network The first railway line in the kingdom predates the unification of Saudi Arabia. The 1,050 mm (3 ft 511⁄32 in) narrow-gauge Hejaz railway, that ran from Damascus to Medina, began construction in