THORNDIKE, Maine — With 440 square miles, RSU 3 in western Waldo County is one of the largest geographic school districts in the state.

The district’s size creates some tough consequences, including the high cost of transportation in the far-flung, rural district and the pre-dawn bus pickup times for some of the most remote students.

Long before the sun comes up on midwinter days, middle and high school students wait for the bus to come as early as 5:45 a.m. Some ride as long as 80 minutes to get to the school complex in Thorndike. After the bus drops them off, the drivers go back over the same routes to pick up younger children.

Next year, all of that will change. The RSU 3 board of directors earlier this month voted to consolidate bus routes, dropping from a two-tiered transportation system to a single bus run. The change will mean that older students will ride with the little kids, that the high school and middle school will start their day significantly later, that the elementary schools will start earlier and that some of the 18 bus drivers will see their workdays reduced.

The move also will help save the school district an estimated $140,000 annually in gas, maintenance and labor expenses. That might be a drop in the bucket for the district, which has an annual budget of about $18.5 million — $1.5 million of which is earmarked for transportation costs — but every bit helps in hard financial times, officials said.

“This is a major change,” Heather Perry, RSU 3 superintendent, said Thursday. “It will impact every family that rides our buses, which is quite a few.”

About 85 percent of the school district’s 1,480 students ride the 18 buses every day. Many parents were uncomfortable with the idea of the young children riding with older students, according to RSU 3 Director Kathy Cunningham of Liberty, who voted against switching to the single bus run during the March 12 regular meeting.

“I was against it for a number of reasons,” she said.

Although her primary concern was for the bus drivers, some of whom may lose their benefits down the road, she said she did hear from a number of concerned parents.

“I just worry about the mixture of the kids,” she said. “The 10-year-olds and the 11-year-olds and the effect that the high school kids might have. The things they might hear at that age. It’s a concern.”

But Perry and director Rachel Katz of Troy said that school officials are working to mitigate the worries. They will survey students this year to find out their own concerns about the combined bus run, and then work to create a program where older students can mentor younger children.

“I know the teenagers in my community are good kids,” Katz said, adding that her son will start kindergarten in the fall. “I think we need to have faith.”

Cunningham said she thinks that the time changes stemming from the altered bus runs will be positive for the district.

“I like the later start for the high school and the middle school, because I don’t like the kids waiting out there in the dark,” she said.

Next year, the start time at the middle and high schools may be pushed to 8:15 or 8:30 a.m. — about an hour later than the current start times.

Ray Shute, the district’s transportation director, said that none of the 18 full-time bus drivers will lose jobs because of the change, but there will be a reduction in some hours.

Katz said the drivers will all keep their benefits at least through the end of the coming school year.

According to Perry, the shift to a single run will allow the district to increase instruction time at outlying elementary schools by about 40 minutes each day.

“In talking with staff, all of us are very positive about it,” she said.