The easiest and quickest way to traverse the crowded city is on the subway, which serves all the main areas of interest. Station signs are written in English as well as Korean, and most lines have English announcements too. Subways are extremely crowded during the morning and evening rush hours, but are generally safe, though plagued with hawkers and beggars. Tickets are bought from vending machines or at ticket windows. Buses are frequent and cover the whole city, but tend to be very crowded. Tickets can be bought on board, or debit tickets can be purchased. Taxis are readily available. Regular taxis (orange, white or silver) charge an initial fee and have a complex system of metering thereafter. Black luxury taxis, called Mobeom taxis, are superior both in condition and service.