Joshua Aaron Byrne, 21, of Ashmont, pleaded guilty to the manslaughter of Wagga man Craig Smith when he faced Wagga Local Court on Wednesday.

A co-accused, Batlow man Matthew Thomas Cahill, 19, also pleaded guilty to manslaughter at a court hearing earlier in the month.

Mr Smith, a 53-year-old husband, father and financial advisor, died when Byrne's VE Commodore ploughed into his vehicle in Coleman Street on October 23, 2017.

According to a statement of agreed facts tendered to the court, both Byrne and Cahill had been attending the Wagga TAFE campus on the morning of the crash as part of an automotive course.

Just before 10am, the class broke for "morning smoko".

It was common practice for some of the students to go to a nearby cafe and Cahill and Byrne, a provisional P1 licence holder, each had two passengers in their cars.

According to court documents, the two drivers had pulled up next to each other at a red light at the intersection of Edmondson and Coleman streets.

After the lights changed, both men accelerated aggressively through the intersection and started a street race.

The speed limit along Coleman Street at that time of the day was 50km/h.

A large number of witnesses described seeing and hearing the two vehicles racing each other at very high speeds.

While the two drivers were racing, Mr Smith was in a Falcon ute parked in Coleman Street, on the same side as Byrne and Cahill were travelling.

The court heard that at some point before the impact Byrne, who was travelling well above the speed limit, crossed to the wrong side of the road to overtake Cahill's car. However, by the point of impact he was in the correct lane.

About the same time as Byrne started overtaking Cahill's vehicle, Mr Smith began a lawful U-turn, intending to drive towards the intersection of Edmondson and Coleman streets, according to the facts.

As Mr Smith was turning, the front of Byrne's vehicle collided heavily with the driver's side door of the ute. Mr Smith was killed instantly.

The impact forced Mr Smith's ute to travel about 30 metres along Coleman Street, where it came to rest on the wrong side of the road, with Byrne's vehicle still attached to it.

The impact caused the tray of Mr Smith's ute to almost completely detach from the cab.

The transmission of Byrne's car was completely detached from the motor and chassis of his vehicle.

Byrne and one passenger were able to free themselves from the car, but the second passenger had to be freed by emergency workers. Cahill's vehicle avoided the collision and he and his passengers attempted to help at the crash scene.

According to the statement of facts, when Byrne got out of his car he was upset and admitted to a witness at the scene that the accident was his fault and he had been driving at more than 100km/h.

During a later police interview, Byrne claimed he had always been the lead driver and travelling at 60km/h or 70km/h. He denied racing.

The court heard that two-and-a-half seconds before the airbag in Byrne's car deployed his vehicle was recorded at 143km/h, and was still travelling at 130km/h half a second prior to the impact.

Byrne was bailed to appear in Wagga District Court on October 11. Cahill, whose bail was previously revoked, is due to appear the same day.