Investment in urban public transportation involves strategic decisions regarding the organization of transit lines in the urban space and the choice of their technology in addition to the size of both fleet and vehicles of each line, and their spacing (lines density). The parametric city model (PCM) of Fielbaum et al. (Transp Res Part B Methodol 94:298–338; Netw Spat Econ 17:343–365) was created to conceive and decide a structural design - the first step of the strategic design - in real size problems, representing the city through zones and centers and evaluating predetermined lines-structures considering a single technology. In this paper the scope and capabilities of the PCM are expanded to help the structural design of urban transit systems, by opening the search for the type of lines-structures studied and considering two technologies (modes), noting that the simplified representation constitutes a useful tool for transport policy that departs from the usual “black-box” procedures. The approach is applied to a PCM version of Santiago, Chile, showing that schemes different from feeder-trunk might be convenient. The results support the options presently taken in Santiago based upon subway expansions but changing the role of the bus system.

对城市公共交通的投资涉及有关城市空间公交线路组织及其技术选择的战略决策，以及每条线路的车队和车辆规模及其间距（线路密度）。Fielbaum 等人的参数化城市模型 （PCM）（Transp Res Part B Methodol 94：298–338;Netw Spat Econ 17：343–365）的创建是为了在实际大小问题中构思和决定结构设计 - 战略设计的第一步，通过区域和中心表示城市，并评估考虑单一技术的预定线路结构。在本文中，通过打开对所研究的线路结构类型的搜索并考虑两种技术（模式），扩展了 PCM 的范围和功能，以帮助城市交通系统的结构设计，并指出简化表示构成了偏离通常“黑匣子”程序的交通政策的有用工具。该方法应用于智利圣地亚哥的 PCM 版本，表明不同于 feeder-trunk 的方案可能很方便。结果支持了圣地亚哥目前基于地铁扩建但改变公交系统角色的选择。