Ashley Talbot, 15, died at Maesteg Comprehensive School in December 2014 after a crash with a minibus driven by a teacher as the school day ended.
The girl said she saw Ashley run between two buses with a friend before the collision happened.
Teacher Chris Brooks was questioned by police but no action was taken.
About 1,000 children were leaving the site in Bridgend county on foot, in buses or cars. On Monday, the jury was told there was regularly "major chaos" outside the school.
The inquest in Aberdare heard the girl had been on a different bus waiting to leave when she saw Ashley with a single earphone in his ear.
She heard three beeps from a vehicle and then saw  Ashley run between the buses before colliding with the minibus.
She said he was thrown onto the bonnet and landed on the floor before the wheel went over him.
Mr Brooks got out of the minibus and ran to the back of it and then to the school to get help. Teachers and bus drivers attempted to give first aid.
She said in a statement she had previously witnessed five near-misses when children had been moving between buses, causing cars to beep and brake.
Other children gave statements saying they had been involved in near-misses but had not reported them because they did not consider them to be serious enough.
Many pupils reported seeing Ashley running with his friend towards the buses on the day he died.
Ashley's friend, who was injured by the minibus, said in a statement he saw it "one or two seconds" before he was hit but could not avoid it and had only heard the engines of the buses which were "quite loud".
He saw Mr Brooks looking ahead and driving at around 10mph.
He felt he and Ashley were to blame for the collision and they should not have been running, adding they had been taught when they were young to "stop, look and listen".
He said they were both racing to get a seat at the back of the bus.
Another child who was on the minibus described seeing Ashley being hit and go underneath, while another passenger described it as feeling like "driving over a speed bump".
One child said in a statement that he had "nearly been knocked over twice at the same location".
He said he had been crossing the road between the buses when a minibus was coming towards him but did not report it because "such occurrences happen nearly every day"
A female pupil told the jury in a statement that she and a friend had nearly been knocked over by a taxi at the same location a couple of weeks before Ashley's death.
However other pupils said they had not been involved in near misses, and they had received instruction on road safety when they joined the school.
The inquest is continuing.

Petra Atkinson, 42, died in hospital after what Humberside Police described as a "domestic incident" at a property in Heather Avenue, Withernsea.
Tony Jobling, of Heather Avenue, appeared at Hull Magistrates' Court charged with murder.
Mr Jobling was remanded in custody to appear at Hull Crown Court on 8 September.
The cause of death has not yet been revealed.
A girl who witnessed the death of a teenage boy hit by a minibus at his school has told his inquest she had previously seen five near-misses.
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