In Metroville, the KP subway line follows the riverfront from downtown to the neighborhoods surrounding the university. No matter how many trains the subway runs on the KP line, there are always congestion and delays on the KP line. The subway submitted a proposal for an alternate subway line that would travel from downtown to the neighborhoods surrounding the university via the inland neighborhoods, hoping to draw some of the congestion from the KP line. The city hired urban planning consultants who concluded the subway's proposal of a new line would not reduce commuter congestion on the KP line.

Which of the following, if true, most helps to explain the urban planning consultants' position?