Currently, the green, sustainable development of metropolises is hindered by problems caused by Large-scale Instantaneous Peak-demands for Passenger-transportation (LIPP), such as traffic congestion and air pollution. To mitigate these problems, we propose a new type of demand-responsive service as an alternative to inefficient "door-to-door" service. The proposed service is based on service units designed to aggregate passengers for shuttle service. To guarantee service quality and efficiency, a maximum passenger walking time constraint, a request rejection mechanism and a scheme for ensuring solution feasibility are considered. Through numerical experiments, we prove the following: (i) the proposed transport option exhibits better performance (by 40.37% for passengers and by 35.79% for operators) than the door-to-door transport option for solving real cases. (ii) By testing different datasets, we prove that the proposed service is more suitable for the request distributions that are spatiotemporally concentrated. (iii) Regarding the individual components of the proposed clustering-first, routing-second solution framework, the proposed soft clustering algorithm exhibits better performance than the classical hard clustering method (by 8%), and the proposed routing algorithm is 1.5 times more efficient than the commercial solution software GAMS. Sustainability 2019, 11, 5025 2 of 28This study is motivated by the desire to seek a new type of demand-responsive service, called large-scale instantaneous-peak-demand-responsive express shuttle service (LIPDRS), that can accommodate the LIPP of a metropolis, while balancing the benefits to operators and passengers. As an alternative to "door-to-door" transportation or frequency services, LIPDRS requires passengers to gather at certain locations, from which they are served by shuttles. Therefore, the LIDPRS design process involves first assigning passengers to certain service units and then transporting them along certain routes. LIPDRS has the advantages of a large capacity (ability to accommodate occasional massive demands), high flexibility (planning based on dynamic phone/Internet requests), low cost (affordability for passengers) and an acceptable level of convenience (passengers are required to gather at certain locations to be served in accordance with their requests). With these advantages, LIPDRS is an innovative means of increasing accessibility between high-circulation areas in a metropolis, such as residential districts and central business districts. As a complement to passenger transit systems, LIPDRS can help solve mobility and accessibility problems in a metropolitan context. In addition, this new transport option can encourage people to reduce their proportions of travel by private cars and thus reduce the cost of and pollution due to urban transportation, thereby improving the sustainability of metropolitan development.However, the realization of LIPDRS comes at the cost of additional complexity. Since passengers are required to gather at certain locatio...