The Minneapolis School District's decision to have high school students use public transportation to get to class instead of riding yellow school buses is paying off with better attendance and better grades according to a new study by University of Minnesota researchers.

And in a surprising finding, it's also helped their social well being, according to the study of the Student Pass program published in the February edition of Catalyst, a monthly newsletter published by the university's Center for Transportation Studies.

Researchers found that absenteeism dropped 23 percent during the 2014-2015 school year according to data collected through surveys of more than 2,000 students and 500 parents.

"It's not surprising, that if you miss the yellow school bus you really have no other way to get to school, meaning you miss half the day or the entire day," said Yingling Fan, associate professor in the Humphrey School of Public Affairs and the principal investigator. "With transit, you can always catch the next bus."

The Student Pass program is a partnership between Metro Transit and Minneapolis Public Schools. It enables students to take unlimited rides on regular-route buses and light-rail trains between 5 a.m. to 10 p.m. daily during the school year.

The Student Pass program debuted for the 2013-14 school year and was expanded district wide the following year. About 6,500 students in grades nine through 12 took nearly 4 million rides on public transportation during the 2014-15 school year. To accommodate students, Metro Transit increased frequency on some routes and added 103 bus trips, the study said.

Students who used their free or reduced-cost Go-To cards to access educational opportunities outside school hours- such as going to a library, museum or taking an after-school course at a community college - boosted their grade point average, Fan said.

"Transit enables students to access additional educational opportunities and participate in additional activities," Fan said.

To that end, it also helps students' social well being, a benefit Fan did not expect find.

"Not having a pass would be social exclusion," she said, noting that students can use their passes to get to jobs or go to movies with friends. "Not having transportation hinders the ability to socialize, and that is a very important human development activity."

The study funded by Metro Transit found that 81 percent of pass users rated their experience as satisfied or very satisfied and 80 percent of parents gave the program the same marks.

Students eligible for free or reduced lunch or were black, foreign-born or from single-parent homes reaped the biggest benefits and rode most, according to the study co-authored by research fellow Kirti Das.

Research found that Student Pass users were more likely to use public transportation after graduation. It also found that the Minneapolis School District saved $1.5 million during the 2013-14 school year on transportation costs and cut it carbon footprint.

“We believed from the beginning that the Student Pass program would benefit students, schools, and Metro Transit,” said Metro Transit general manager Brian Lamb. “We’re pleased to have the data that explain and confirm the benefits.”