Transit network conditions change everyday. While those changes should be considered for modifying a transit network, formulating and optimizing the whole transit network may be a costly, difficult task. This article uses a developed transit network design model to examine how optimal transit networks should be developed based on changes in input elements of the transit network. Three major inputs—demand, travel speed, and transfer penalty— are chosen for the sensitivity analysis. Different optimal transit networks and their characteristics are generated, and the relationship between inputs and outputs is discussed. Using the sensitivity analysis, three typical transit networks—transferoriented transit, transfer-avoidance transit, and directly-connected transit—are introduced. Optimal types of transit networks are suggested based on transit network situations.