Skid marks could be seen along the road a short distance before the impact point.
The man and his female partner were both riding Harley-Davidsons which were registered to a motorcycle rental company.
One of the first upon the scene were Brendan and Kathy Webb who were travelling only a short distance behind the utility.
"We were heading into town - it could have been us," Mr Webb said.
He said the female rider, who was riding in front of her partner, had moved away from the Meeanee Quay stop sign and headed north on to the expressway.
The man immediately followed and did not appear to see the incoming utility.
"It hit him square on - he just flew through the air."
The woman rider stopped a short distance up the road after hearing the impact.
"You could see the look of terror on her face," Mr Webb said.
He said the badly injured rider was moving and murmuring, and he and others who were first on the scene kept him still and called for help.
"He had good strong riding gear on - I think that saved a lot of damage."
Mrs Webb and others comforted the man's partner and the utility driver.
Hawke's Bay Roading Police Group Senior Constable Ken Hunt was quickly on the scene as he had passed through the intersection only a few minutes earlier while on patrol.
The intersection was closed to right-turning northbound traffic for about 90 minutes although cars were detoured left on to the expressway, and then able to turn and head north under police directions.
Mr Hunt said he would be interviewing the rider after he had recovered sufficiently.
The man's partner was offered a place to stay during the recovery process by at least two people at the crash scene.
Police would not comment on whether the man may have become confused as in Finland vehicles coming from the right would be on the far side of the road, as they drive on the right in that country.
