The United Arab Emirates have an extensive and well-developed road network, principally in the northern coastal area where the main population centres are located. Many of these roads have been improved to become multi-lane dual-carriageway motorways, coping with the high demand for road transport. Speed limits are 120 km/h (75 mph) on freeways, 100 km/h (62 mph) on rural roads, and 60 or 80 km/h (37 or 50 mph) on urban dual-carriageways. Heavy trucks and buses are installed with speed limiters to prevent overspeeding. Bus services were introduced in Abu Dhabi by the Emirate in 2008 with four routes which were zero fare in their pilot year. At the end of 2011, bus services in the Emirate of Abu Dhabi provided more than 95 service routes with 650 buses to transportation 50 million passengers in the region. In the Bus Network Plan in 2013, 14 bus routes were operated in Abu Dhabi City. In Dubai, the Roads and Transport Authority (RTA) operates bus services under the name DubaiBus. Buses in Sharjah are operated by Mowasalat, and in Ajman by Ajman bus. There are also buses operating between the different Emirates due to the lack of rail connectivity, although this is planned to be rectified in the near future.