OG详解-OG5 阅读 Q9

Choice B is the best answer because it most accurately describes how the underlined portion functions in the text as a whole. The first sentence explains that reproducing the high ridership of Mexico City’s public transit system in other cities by implementing some of its features, such as its low fares, is unlikely to guarantee significant ridership increases in those cities. The following sentence introduces a study by Guerra et al., whose findings—namely that choice of transportation mode in urban centers in Mexico is influenced by a variety of local contextual factors—support this claim. The first part of the last sentence concedes that features of transportation systems likely do have some effect on ridership numbers, but the underlined portion reiterates the study’s conclusion by stating that there is an “irreducibly contextual dimension” to peoples’ choice to use public transportation: that is, there is a complex mix of local contextual factors—including population density, spatial distribution of jobs, and demographics—whose influence over an urban center’s transit ridership is unique to each location, and it is unlikely that simple changes to transit system characteristics could negate the influence of those contextual factors. Thus, the underlined portion explains why it is challenging to influence transit ridership solely by changing some of a transit system’s characteristics.
Choice A is incorrect. Rather than objecting to the argument of Guerra et al., the underlined portion reiterates their argument by stating that there is an “irreducibly contextual dimension” involved in transportation mode choice; in other words, transportation mode choice in urban areas of Mexico is strongly dependent on contextual factors that are unique to each urban area. Choice C is incorrect because it mischaracterizes the text’s central claim, which is that transit ridership is the product of a complex mix of contextual factors and transit system features, not that a characteristic associated with Mexico City’s high transit ridership was found to have no association with high transit ridership elsewhere. Additionally, the underlined portion does not illustrate a claim, but instead restates the findings of Guerra et al. Choice D is incorrect. Although Guerra et al. demonstrate that population density, the spatial distribution of jobs, and demographic characteristics—factors that comprise the “contextual dimension of transportation mode choice”—influence transit ridership, the underlined portion does not substantiate—that is, provide evidence in support of—this assertion. Rather, the underlined portion merely restates a study finding that explains why simply altering a transit system’s features would be unlikely to induce significant increases in transit ridership.