Hill was seen driving a ute north of SH3 Bulls at 11.25 that night, the summary of facts said.
During his drive, Hill was seen drifting between the left hand fog line, to the centre line, and back again "numerous" times.
"At one stage, the defendant's ute came to a complete stop between two lanes while still in the 100km/h zone, and was nearly struck by [a] truck as the driver rounded a bend to find the ute just sitting there," the summary said.
After passing through Turakina, Hill entered roadworks with a temporary speed limit of 30km/h. There were two workers in the area.
The victim was wearing high visibility clothing, a helmet, and was carrying a green "light stick" as she placed cones on the centre line.
The road has three lanes - two uphill northbound lanes and one downhill lane. At the time, one of the uphill lanes was coned off and not in use.
Hill, who was travelling above the 30km/h speed limit, came through the area "straddling the centre line".
The victim's coworker saw him and tried to slow him down by waving her light stick, but Hill didn't respond, and hit the victim with the left front of his vehicle, "causing her to ride up on to the bonnet before falling to the ground".
Hill stopped, didn't get out, then drove off, the summary said. He was stopped by police a few kilometres up the road.
The victim suffered gravel rash to the whole right side of her face, as well as on her leg, shoulder, elbow, and hands. She suffered cuts, scratches, and bruises, as well as "severe" damage to three ligaments in her left knee.
She also suffered sore shoulders, eyes, blurred vision, a sore jaw, ribs and chest, and had difficulty breathing.
The victim also had to have six stitches on her chin and multiple stitches for a "large hole" on the right side of her face.
"She initially also suffered severe nightmares, waking on seeing headlights coming at her several times a night," the summary said.
She was in hospital for 11 days and went through two surgical procedures. She is currently awaiting a third. It is estimated she will be on crutches for three months.
Judge David Cameron remanded Hill to September 26 for sentencing, and referred the matter to Restorative Justice.