I work in transportation so I take some issue with the portrayal of costs associated with using public transportation.
Where I live in a medium-large metropolitan area, I can purchase a 31-day unlimited ride GoTo card for $85, making my daily commute and occasional grocery/doctor/other trips for less than $2.50 a day. I can use transfers to get off the bus, do something, and re-board the bus within 2 hours and finish my trip without any additional cost. I think the author was using the cash fare, but there are good discounts available.
No doubt it is difficult being poor. When I got my first job and started paying back student loans, I had to ration my dinnertime mac and cheese and hot dogs to get through to the next paycheck. There are better ways to save money, or not to waste money. A good public transportation network can provide people with access to jobs and education opportunities for much less money than driving, though it is usually less convenient.