Adam Beardsmore and friend Daniel Hay, both 23, died when the car they were in became airborne and crashed into a tree after a collision with the ute along a section of the Mornington Peninsula Freeway in Dromana shortly after 1pm on November 17, 2014.

Prosecutors allege the driver of the ute, Nicholas George, caused the collision that resulted in both cars crashing. Mr George was also injured.

Mr George, 50, has pleaded not guilty to two charges of culpable driving causing death.

On the first day of his trial, the court was told Mr Beardsmore was driving to Dromana with Mr Hay to inspect a four-wheel drive that had been advertised for sale.

In an opening address, prosecutor Andrew Grant told a County Court jury the owner of the four-wheel drive was at his home, outside, when he heard the roar of an engine "like on a drag strip" before he heard tyres screech and a loud bang.

Mr Grant said motorists on the freeway reported seeing Mr Beardsmore's blue Ford sedan, with Mr George's black Holden ute behind it,  travelling at excessive speed.

One motorist estimated the vehicles were driving at 200km/h, the jury heard, but most put the speeds at between 140km/h and 160km/h.

One driver told police the car and the ute were two metres apart when they passed her at an estimated speed of 150km/h, Mr Grant said.

The roar of the two vehicles was described as "horrendous" by one driver, the prosecutor said, while another told police the sedan and ute zoomed past "as if we were standing still at a set of traffic lights".

The speed limit on that stretch freeway was 100km/h, the trial heard.

Mr George's lawyer is yet to address the jury.

The trial continues.