This study analyzes various methods of providing transit services in low-density areas. These areas can be classified into two major categories. First, suburban areas of medium and large cities; and second, entire medium and small cities which have low population densities. One of these types of areas is found in most cities. The focus of this study is the type of transit network and operation in which special transit centers are organized at which vehicles from several different lines converge at the same time, enabling passengers to transfer between any two lines, and then depart in their respective directions. This type of service is called timed transfer system, or TTS. Thus instead of individual transit lines, usually with inconvenient transfers in low density areas, TTS represents a coordinated transit network which passengers can utilize for travel between any two points in the served area with reasonable convenience and average travel speed. To provide a thorough description and analysis of TTS, and to define precisely its role in urban areas, this study first presents a systematic review of various types of transit services, networks and methods of operation, defining characteristics, advantages and disadvantages of each one. A later part of the report (sections 4 to 7) focuses on the TTS, presenting all its basic elements as well as methodology for their planning and implementation. An example of TTS planning is given in section 8.