A 74-year-old driver 'lost control' of the Georgia school bus that overturned onto a busy highway while transporting more than 20 high school football players, authorities said.

A school bus carrying the football team from Salem High School in Conyers, a suburb outside of Atlanta, flipped on State Route 138 in Rockdale County, around 10.48pm on Friday.

The Georgia State Patrol (GSP) told the Daily Mail on Saturday morning that the Yellow 2025 Freightliner bus was being driven by Walter Hackett, 74, according to preliminary findings.

Hackett, of Conyers, was exiting Interstate 20 eastbound and trying to make a right turn onto State Route 138 when he lost control of the vehicle, according to the GSP.

The bus traveled across all the lanes of State Route 138 and hit a Black Kia Soul being driven by Covington resident Calvin Harling, 35, in the left northbound lane.

Harling's Kia rotated counter-clockwise approximately 180 degrees and ended in the right northbound lane, per the GSP.

The school bus continued off the roadway and onto the east shoulder of State Route 138, where it started to overturn and rolled.

It nearly made one full rotation before it came to an uncontrolled rest on the passenger's side, according to the GSP.

The GSP said Saturday that all the students in the bus had been accounted for.

Some were taken in for medical treatment by their parents, while others were transported to the hospital by ambulance.

Authorities added that one student was also flown via Life Flight, though more details were not revealed.

Hackett and Harling were both taken in for treatment, as well. Further details about their conditions were not released.

The accident is still being actively investigated, the GSP said.

Harling's sister, Breauna Harling, confirmed on Facebook that her brother had been involved in the school bus crash and said he was at the hospital as of Saturday.

'His car is totaled, but I thank God that his life was preserved!' she wrote. 'I'm just glad they don't have "fatal" next to my brother name!'

On Saturday morning, Rockdale County Public Schools Superintendent Dr Stephanie S Johnson said there were 22 students and three adults rushed in for medical treatment.

'Our hearts are with the Salem High School football players, athletic trainers, coaches, staff, and families impacted by last night's bus accident,' Johnson wrote.

She added that she was 'deeply grateful that there were no fatalities,' adding that 'many' people had already been treated and released.

The Rockdale County school district told local news outlets on Friday that, in total, 27 people had been involved in the crash.

The bus was carrying 17 football players, seven trainers, two coaches and one driver. At least two medical helicopters were requested, the district said.

Head coach Fredrick Green was working on locating where all the affected team members were taken for treatment.

Children's Healthcare of Atlanta Arthur M Blank Hospital was placed on standby for the 'possibility of a mass casualty event,' Fox 5 Atlanta reported.

The hospital took in at least three patients who were treated and released, according to 11Alive.

Videos of the bus crash showed a large emergency response with firefighters and ambulances responding to the scene.

One side of the bus's roof collapsed completely, while the front was smashed in and windows were shattered all over.

Salem High School had played an away game against Greater Atlanta Christian in Norcross at 7.30pm on Friday night.

The high schools, both in the Atlanta area, are roughly a 50-minute drive from each other.

Katherine White, Greater Atlanta Christian School's vice president of advancement, said she was 'especially praying for healing for those who were injured and for God's peace and comfort for everyone impacted.'

'Having just hosted your team on our campus last night, we especially want to reach out and offer our care and support during this difficult time,' White said, according to AtlantaNewsFirst.

Georgia State Route 138 was temporarily shut down after the crash, with travelers advised to seek alternate routes.

The Daily Mail has reached out to Rockdale County Public Schools for further comment.