The Metro bus service has created a new bus route to accommodate Portland’s high school students, who will no longer be served by yellow school buses when the school year begins Sept. 2.

Route 9, which launched this week, loops around the city, hitting Portland, Deering and Casco Bay high schools, and includes some service into the North Deering neighborhood.

Route 9A travels clockwise from the Portland Public Library via Congress Street to Stevens Avenue, where Deering High School is located. It then hits Allen Avenue, where Casco Bay High School is located, returning downtown via Washington Avenue. Route 9B will run counterclockwise on the same route.

Officials approved the use of Metro buses as part of a plan to add 20 minutes to the school day for all grades and reorganize the yellow school bus system. Moving high school students to Metro buses freed up the district’s yellow bus fleet to make more runs in a shorter amount of time to accommodate changes in start times for elementary and middle school students.

High school students received their student Metro passes in June, along with code of conduct and safety tips, and they were asked to sign a form agreeing to follow those rules. They were allowed to use the passes, which double as student ID cards, this summer to get accustomed to the Metro service, but the passes will only be good during the school year after Sept. 2.

In July, Metro reported 5,882 rides by high school students. Portland has about 2,100 high school students.

On the Metro website’s “trip planner” application, students can enter their home address and get information about the closest Metro stop and how much time it will take to get to their school. A survey of student addresses found that 82 percent of Portland’s high school students live within a quarter-mile of a Metro stop.

Supporters of the change note that in the past, yellow bus service wasn’t available to students who lived within two miles of their high school, while the Metro pass is available to all high school students. Many students reported they were already using Metro service during the school year because they didn’t qualify for yellow-bus service.