Luxembourg Wants to Solve Congestion with Free Public Transport

I'm slightly confused by the last part in the article

"Even though free public transportation has existed in Tallinn, Estonia for over six years, there has been no indication that mobility and opportunities for low income residents have improved."

Following the link to the study:

"Almost a year after the introduction of FFPT, public transport usage increased by 14 % and there is evidence that the mobility of low-income residents has improved. The effect of FFPT on ridership is substantially lower than those reported in previous studies due to the good level of service provision, high public transport usage and low public transport fees that existed already prior to the FFPT."

This is strange reporting