The success of transit systems, traditionally gauged through ridership metrics, must also be assessed via transit accessibility because accessibility to destinations indicates the quality of service that transit provides. Using a structural equation modeling approach, we explain transit accessibility and transit ridership in 2017 for 50 large urbanized areas in the United States as dual outcomes dependent upon population size, urban form, and transit service provision. Also, we examine transit accessibility as a factor that influences transit ridership. We find that transit service provision strongly influences both transit ridership per capita and job accessibility provided by transit. Further, we find that transit accessibility, in turn, offers a moderate boost to transit ridership. Population density results in higher transit accessibility directly by making destinations easier to reach and indirectly by increasing the amount of transit services provided. Other built environment and transit service variables were examined but did not improve the models’ explanatory power. Disaggregating the effects of fixed-guideway (i.e., rail) and non-fixed guideway transit (i.e., buses in mixed traffic), we find that fixed-guideway transit has a more substantial effect on transit accessibility, while non-fixed guideway transit has a larger effect on transit ridership per vehicle mile.

交通系统的成功，传统上通过乘客量指标来衡量，也必须通过交通可达性来评估，因为目的地的可达性表明了交通提供的服务质量。使用结构方程建模方法，我们将 2017 年美国 50 个大型城市化地区的公交可达性和公交乘客量解释为取决于人口规模、城市形态和公交服务提供的双重结果。此外，我们将公交可达性作为影响公交乘客的一个因素进行了研究。我们发现公共交通服务的提供对人均公共交通乘客人数和公共交通提供的工作机会都有很大影响。此外，我们发现公交可达性反过来又适度提高了公交乘客量。人口密度直接通过使目的地更容易到达并通过增加提供的交通服务数量间接导致更高的交通可达性。检查了其他建筑环境和交通服务变量，但没有提高模型的解释力。分解固定导轨（即铁路）和非固定导轨交通（即混合交通中的公交车）的影响，我们发现固定导轨交通对交通可达性的影响更大，而非固定导轨交通对交通可达性的影响更大。对每车英里的公共交通乘客量的影响更大。