This paper proposes a bimodal urban transit system with point-to-point transit (PPT) services considering the emission. PPT is designated to serve passengers with long travel distances, connecting two transport hubs with few intermediate stops. We focus on the bimodal system of FRT and PPT, formulating the joint design problem as a mixed-integer program through a parsimonious continuum model. The relative location between FRT and PPT stations varies over space, which complicates route choice analysis. We overcome the challenge by approximating the costs to access transit stations at an aggregate origin-destination level. This is validated by Monte Carlo simulation. Our findings show that the proposed system is both more cost-efficient and eco-friendly than the regular system in cities with high travel demand. However, its performance deteriorates as demand drops. Such a demand threshold is systematically examined in cities with different features such as geographical sizes, PPT speed, and income levels.

本文提出了一种考虑排放的具有点对点交通 (PPT) 服务的双模式城市交通系统。PPT 旨在为长途旅行的乘客提供服务，连接两个交通枢纽，中间停靠点很少。我们专注于 FRT 和 PPT 的双峰系统，通过简约的连续统模型将联合设计问题表述为混合整数规划。FRT 和 PPT 站之间的相对位置随空间而变化，这使路线选择分析变得复杂。我们通过在起点-终点总水平上估算访问中转站的成本来克服挑战。蒙特卡罗模拟验证了这一点。我们的研究结果表明，在出行需求高的城市，所提议的系统比常规系统更具成本效益和环保。然而，随着需求下降，它的表现会恶化。在具有不同特征的城市（如地理规模、PPT 速度和收入水平）中，系统地研究了这样的需求阈值。