Here is a blogger who has done hard work to collect statistics on paying for transportation

https://reports.mysidewalk.com/bfb9734ce2

Worcester, MA, case for fare-free public transit

Public transportation is treated differently. The Worcester Regional Transit Authority charges most adults $1.75 per trip to board the bus, a disincentive to make use of what could be a cornerstone of the region’s transportation network. Ridership is dropping, declining 23 percent between 2016—before the latest fare hike—and 2018. Last year had the fewest passenger trips since a driver strike in 2005, and the lowest in a non-strike year since tracking began in 1991.

http://www.wrrb.org/wp-content/uploads/2019/05/WRRB-FareFree-Transit-Report.pdf 

Affordability As A Transportation Planning Objective | Planetizen

Affordability As A Transportation Planning Objective | Planetizen: "The 2009 National Household Travel Survey asked respondents to rate the importance of six transport problems: traffic safety, congestion, price of travel, availability of public transit, and lack of walkways or sidewalks. Virtually every demographic group rated affordability (“price of travel”) most important, as indicated in the graphs below."

Housing and Transportation Affordability

Housing and Transportation Affordability Index

Economic value of walkability

Consumer Cost Savings Walkability affects consumer transport costs. Improved walkability allows consumers to save on vehicle expenses (“Affordability,” VTPI 2008). For example, one study found that households in automobile-dependent communities devote 50% more to transportation (more than $8,500 annually) than households in communities with more accessible land use and more multi-modal transportation systems (less than $5,500
annually) (McCann 2000).

Read more...
http://www.vtpi.org/walkability.pdf