include the other ethnicities among the population of Karaj. Transport Railway Karaj is connected by railway and highways to Tehran 40 km east and Qazvin 100 km northwest, and by commuter rail to the subway system of Tehran. The city is served by an urban railway organization established on 21 December 2001. It is also served by the Karaj Metro Station which was established on 7 March 1999, and is located in the south-eastern Karaj, near Tehran–Qazvin Freeway. Road The highway system of Karaj includes Tehran–Karaj Highway, Karaj Special Road, and the old road of Karaj (Fath Highway). Bākeri Expressway is one of the main north-to-south routes in west Tehran, which is connected to the Tehran–Karaj Highway. Tehran–Karaj Highway is one of the busiest sections in Iran with AADT of 217084. Karaj–Qazvin has an AADT of 79606. The aerial transport of Karaj is served by the Payam International Airport, which was established in 1990, and was officially opened in 1997. Bus Currently, the total number of buses in Karaj and the suburbs are 1,600 units. More than 80 lines serve citizens. Preparing Alborz Card can reduce the cost of travel tickets. Metro Karaj Metro is an efficient way to travel inside the city. One line connects west and east of the city (from Karaj Station to Golshahr Station). It continues eastward until Tehran. On its way to Tehran, it stops at Chitgar park and Azadi stadium. The second line of Karaj metro (north to south) is under construction. Air Payam International Airport, is an international airport located in Karaj, 40 kilometers (25 mi) from Tehran, in the Alborz Province of Iran. The airport was established in 1990, but was not opened officially until 1997. Payam Aviation Services Co. operates the airport as part of Payam Special Economic Zone. Payam Air previously operated an airmail hub at the airport. Currently, this airport and its special area are used for purposes such as cargo transit, commercial transportation, and goods mail in the development of the country's communication and information technology industries. Economy The economic base of Karaj is its proximity to Tehran. It is due to the transportation of products between Tehran and the Caspian Sea. Chemicals, fertilizers and processed agricultural goods are also produced in the city. Zowb Āhan, the avenue leading to an industrial plant, is located at the south of Ostandar Square. Zowb e Āhan or Zowb Āhan, literally