Corby's Joseph Rooney died of a chest injury after his Audi crashed off the road and into a tree.
Passers-by tried to save his life using CPR but Mr Rooney's injuries were too serious and he died on the scene.
Mr Rooney, of Stanion Lane, known in Corby as Gypsy Joe, was found with a balloon in his left hand and there were nitrous oxide canisters in the car. He also had other drugs in his system.
An inquest this morning (Wednesday, July 28) heard how the 47-year-old had been seen driving at speed minutes before the incident on the A4300 near Little Oakley at about 3.30pm afternoon of October 25 last year.
Evidence was read to the court from a witness who saw Mr Rooney's Audi A8 in Geddington Road.
He said: "I was driving along Geddington Road. I'd just gone past the Jet petrol station when I saw an Audi travelling behind me.
"I came to the roundabout near the Holiday Inn.
"I accelerated after I had entered the carriageway and moved into lane two.
"I could still see the Audi travelling behind me.
"I saw it collide with the driver's-side kerb which would have been in the central reservation.
"It slowed right down and I remember thinking the driver must have panicked a bit.
"I took the second exit into Stamford Road and could not see the Audi behind me. As I prepared to turn left to Stanion I saw the Audi behind me and it came quite close to me and had to swerve."
Later the witness heard a helicopter and remarked to his wife that he wondered if the driver of the Audi had had an accident.
Police were called to the A4300 Stamford Road close to its junction with Little Oakley at about 3.30pm by the car's automatic distress signal. A patrol officer recognised Mr Rooney as a man he knew and said that he had spent more than two hours with him just two weeks before the accident.
Emergency response paramedic Ian Pratt said that when he arrived on the scene he found the car 100 yards off the road in a wooded area. He found that Mr Rooney was not wearing his seatbelt which was clipped in the holder behind his back.
"He was holding a deflated yellow balloon in his left hand between his thumb and fingers, he said.
"He was not wearing a seatbelt."
Passers-by were carrying out CPR but a defibrillator showed no electrical activity. He was declared dead by a doctor who arrived with the air ambulance at 4.05pm.
Passenger Jane Hill was wearing her seatbelt and she survived the crash with serious injuries.
Evidence from another police officer read to the inquest said he arrived on the scene later and used a fingerprint scanner to confirm Mr Rooney's identity. The scanner showed his fingerprints to be those of James Thomas McCann, an alias used by Mr Rooney.
Corner Anne Pember heard that a number of medium-sized canisters of nitrous oxide were found in the back of the car along with several popped balloons. Also known as laughing gas, the drug is normally sold in canisters and inhaled from a balloon. It can give users a feeling of calm or euphoria but can also cause them to feel dizzy or prevent cohesive thinking.
A pathologist's report gave Mr Rooney's cause of death as a chest injury probably caused when he hit the console in front of him during the crash. He also had a spinal injury. Toxicology reports found the presence of diazepam and a designer benzo called flubromazolam which has a potent sedative effect. The same drug was also found in the system of another Corby man whose inquest was held last month.
There is no test for nitrous oxide in the system of a deceased person but Mrs Pember said that she believed that Mr Rooney had taken the drug.
A traffic collision expert said that the car had been seen driving erratically and that the cannisters of nitrous oxide were 'not the normal size you'd expect to see' but were larger one-litre cannisters.
He said that the driver had not correctly negotiated a bend in the road and had hit a road sign, then left the carriageway before travelling 86 metres along the grass and hitting a large tree.
Coroner Ann Pember said that Mr Rooney had clipped his belt in and then sat on it to stop automatic seatbelt alarms going off.
Returning a verdict of accidental death, Mrs Pember said: "Mr Rooney failed to negotiate a moderate left-hand bend, collided with a large directional sign and subsequently a large tree.
"It's clear he'd had a therapeutic dose of diazepam and some flubromazolam which can cause drowsiness.
"It's likely he had used nitrous oxide. I feel he was impaired to drive at speed which resulted in a collision and his untimely death."
Mr Rooney's funeral caused controversy among local people after a large number gathered him during the pandemic to remember him.