It’s not unusual for Claire Mudd, a freshman at Eleanor Roosevelt High School in Greenbelt, to arrive 20 minutes late to her foundations of technology class. At least once, Mudd showed up even later, halfway into second period.

The tardiness isn’t Claire’s fault. Her Prince George’s County school bus is chronically late, arriving long after the first bell rings, and part of a district-wide problem that dates to last year.

Schools buses in the county that continue to arrive late have not only caused an inconvenience for students, but parents worry that the ongoing problem could have a negative impact on grades.

“It really puts the kids at a disadvantage, and it’s not fair,” said Sheila Mudd of West Laurel, whose daughter Claire attends the county’s top-performing school. “She is missing the first 20 minutes of a 45-minute class.”