Hayden Beszant knows that if he had not done first aid training, he would have been just another bystander when he came across a crash between a motorcycle and car.
But instead of having to stand aside, wishing he knew what to do, the 18-year-old St John Ambulance volunteer was able to act on his instinct to help.
Hayden, a Leicester College student, and his father were driving to his sister's house when they came across the scene in Saffron Lane, Leicester, two months ago.
The motorcyclist, a takeaway delivery driver, was lying in the road.
Hayden, from Aylestone, said: "When I saw the biker lying in the road I shouted to my dad to stop.
"There were a few people gathered around him but no one else had any first aid knowledge, so I immediately took control of the situation.
"Someone asked if the car should be moved but I said to leave it where it was as it was blocking the lane from oncoming traffic and protecting me and the injured biker."
The first thing Hayden did was to check that someone had called 999 to request an ambulance.
Then the teenager, who is hoping to become a fully-trained paramedic, spoke to the motorcyclist to find out what injuries he had.
"He was complaining of back pain from top to bottom so I asked my dad to hold his head still and together we did this, as well as reassuring the patient, until emergency help arrived," said Hayden.
"Witnesses said that the biker had travelled about a metre in the air after coming off his bike.
"I feared he might have suffered spinal injuries so obviously wanted to keep his head and neck completely still until he could be checked in hospital."
A fast responder paramedic arrived and Hayden helped care for the patient until an ambulance arrived.
Hayden became a St John Ambulance volunteer in September last year, and is a member of the Southfields Unit.
He regularly provides first aid at public events including Leicester City matches, rugby matches and events in the city centre.
"As a St John Ambulance first aider I obviously wanted to use my skills to help the injured biker," he said.
"More people need to know the basics, it could mean the difference between life and death.
"On the day of the accident, there were five or six people around the patient but apart from me not one of them knew what to do. If I hadn't been there and no one had first aid knowledge the patient's condition could have deteriorated and the situation might have been very different."
Recent research by St John Ambulance shows that fewer than one in five people in Leicester knows even basic first aid.
Nick Reynolds, a paramedic with East Midlands Ambulance Service, said: "Knowing what to do in an emergency is vital.
"Hayden was aware of his surroundings and any potential new risks. He was in control and took action to prevent further injury to the motorcyclist.
"Having asked questions of those who witnessed the incident, he armed himself with important information to help our paramedics give the best possible care on scene and throughout the journey to hospital."