The woman said she "freaked out" and pulled over to see if the young man was okay.
"He was so good, so brave. He was reassuring me."
It was the woman's first day as a volunteer driver for the elderly. She said cars driving past stopped and neighbours came out of their homes.
"They were all so amazing."
The woman said she rang the young boy's father, who came to collect him and take him to hospital where his knee was stitched up. She wanted to thank everyone that helped and especially praised the young man.
"I was just amazed at how brave he was, he allayed my fears completely. He was bleeding but still said 'no it's alright, I'm okay'."
The boy's mother Lisa Lomas said her son was recovering well after receiving four stitches.
"He's recovering well, he's very lucky. He's a great little guy."
Mrs Lomas wanted to thank all the people who stopped and helped her son.
"There were four ladies who stopped, I have no idea who they are, just good samaritans, but I want to thank them from the bottom of our hearts.
"It was very kind what they did."
Her son had yesterday off school but Mrs Lomas said he would be returning today.