Bus Rapid Transit (BRT) has proven to be an effective and affordable transportation option for large-sized cities. In these cities, BRT is usually considered an effective complement or substitute for rail-based systems, playing a key role in complex multimodal networks with several massive transport corridors. More recently, medium-sized cities of less than 200,000 inhabitants have also considering implementing BRT as a means of mass transit. These cities usually need only a few of these massive transport corridors (often just one), and they must decide how to structure their services. This report discusses which of the two types of BRT-based networks is best for the social interest in the case of medium-sized cities: (1) Closed BRT, in which buses operating inside and outside the corridor are separated and have different designs, or (2) Open BRT, in which the same buses operate inside and outside the corridor, entering and exiting at different points along a route. To answer this question two models with different levels of detail in terms of a city’s characteristics were developed to represent both agency and user costs. In the first model a classic idealized city approach is addressed, while in the second model the problem is solved for the specific geographic characteristics and constraints of a real city. The results based on both models show that when it is optimally configured, Closed BRT networks offer mid-sized cities higher frequencies and lower waiting times. However, these benefits do not offset the cost associated with higher number of transfers that Closed BRT networks require, as compared to Open BRT networks. Transfers not only affect users due to the transferring experience, but also end up making the entire system slower. Overall, Open BRT shows significantly less Total Costs than Closed BRT in most of the scenarios that were analyzed.

事实证明，对于大城市而言，快速公交（BRT）是一种有效且负担得起的交通方式。在这些城市中，BRT通常被认为是基于铁路的系统的有效补充或替代，在具有多个大型运输通道的复杂多式联运网络中发挥着关键作用。最近，人口不足200,000的中型城市也正在考虑实施BRT作为大众运输工具。这些城市通常仅需要这些大规模运输通道中的几个（通常只有一个），并且它们必须决定如何构建服务结构。本报告讨论了在中型城市中，两种基于BRT的网络中哪一种最符合社会利益：（1）封闭式BRT，其中走廊内外的公交车是分开的，并且设计不同，或（2）打开BRT，其中相同的公交车在走廊的内部和外部运行，沿路线的不同点进出。为了回答这个问题，开发了两种具有不同城市细节水平的模型来代表代理商和用户成本。在第一个模型中，解决了经典的理想化城市方法，而在第二个模型中，解决了实际城市的特定地理特征和约束条件。基于这两种模型的结果表明，当最佳配置时，封闭式BRT网络为中型城市提供了更高的频率和更少的等待时间。但是，与开放式BRT网络相比，这些好处并不能抵消与封闭式BRT网络所需的更多传输次数相关的成本。传输不仅会因传输体验而影响用户，而且最终会使整个系统变慢。总体而言，在分析的大多数情况下，开放式BRT的总成本明显低于封闭式BRT。