A flexible route bus system, serving an area and providing pick-up and drop-off at the users’ doorsteps may be more effective than a conventional bus system in areas with relatively low demand density. Thus, it may reduce the cost per trip and avoid the time and cost to users of accessing bus stops. However, depending on the demand density and circuity of routes, passengers might experience longer travel times and longer wait times. The objective of the thesis is to combine individual many-to-one flexible route services operating in multiple regions, which serve both internal and external demand, and optimize them into an integrated flexible route bus service that offers complete many-to-many transit services for large urban and suburban regions. A total cost function is formulated, and an optimized headway is found for the system. The sensitivity analyses evaluate the influence of input variables on the headway and system effectiveness measures.