Hawke's Bay Road Policing Senior Sergeant Greg Brown said the crash was "disappointing" in light of a high-profile police media campaign last week that highlighted the risks of drivers crossing the centre line.
"We have put a lot of effort into raising public awareness around this problem and to have a crash such as this just days afterwards does not bode well," Mr Brown said.
"People must realise that if you cross the centre line, the chances of colliding with oncoming vehicles is extremely high."
He said Saturday night's incident showed just how easily "things can go wrong in a matter of seconds".
The Police Serious Crash Unit is investigating the crash and Mr Brown said it was not sure at this stage if alcohol or speed had been a factor.
The badly injured driver was taken to Hawke's Bay Hospital and is in a critical condition in the intensive care unit.
"It is so disappointing because we still see people playing Russian roulette by crossing the centre line," Mr Brown said.
"If this driver had stuck to his side of the road this would simply not have happened."
Mr Brown said officers had come across "a lot of people" who when spoken to about crossing the centre line had bemoaned "why are you doing this here?"
Incidents like the Saturday night crash at Kereru provided the most graphic answer, he said.
"It is something we will continue to keep a focus on."
A Napier woman cyclist received critical leg and pelvic injuries after a collision with a truck and trailer unit entering a driveway across the cycleway at Awatoto early yesterday morning. The accident happened about 5.45am.
A police spokesperson said the fully laden concrete truck and trailer had driven out of Waitangi Rd and crossed SH2 into the southern entrance of Winstone Aggregates, which is directly across from the intersection.
The woman had been riding on the cycleway and collided with the truck's trailer.
Police said the driver of the unit had been unaware of the collision and continued into the Winstone Aggregates yard.
After unloading the unit he drove back to the entranceway and saw the woman lying on the ground nearby.
He immediately called for help.
The woman was rushed to Hawke's Bay Hospital.
A hospital spokeswoman said yesterday the cyclist was in a critical condition in the intensive care unit.
The Police Serious Crash Unit and the Commercial Vehicle Investigation Unit are both investigating the crash.