WEYBURN, Sask. -- A driver accused in the death of a pregnant flag person on a Saskatchewan highway must wait until October before learning the judge's verdict.

Keith Dunford, 47, of Regina faces charges of criminal negligence causing death and dangerous driving causing death after 18-year-old Ashley Dawn Richards was fatally stuck and killed during her first day on the job in August 2012.

Dunford pleaded not guilty to both charges on the first day of the trial Thursday.

The court in Weyburn heard Richards moved to Saskatchewan from Lakeside, New Brunswick.

She was thrown about the width of a Canadian Football League field when she was struck by an SUV in a construction zone on Highway 39 near Midale.

Justice Lana Krogan reserved her decision until Oct. 13.

Semi-driver Katherina Neufeld testified that an SUV passed her in the orange zone despite there being no-pass signs up.

She said the vehicle wasn't speeding, but after completing the pass it suddenly swerved to the left and a post went flying.

A man, who she identified in court as Dunford, got out of the SUV. She said she got out of her truck to see a woman in the ditch.

Cst. Nick Melanson described to court a red spatter of blood in the ditch near where the body landed. A blond tuft of hair could also be seen in the middle of the highway before the wind blew it away.

Melanson said Dunford didn't show any signs of impairment. Instead, Dunford was said to be in shock, looking upset. He was also co-operative with police.

A former co-worker who trained Richards, Betty Barabash, told court that Richards was a "bright, young lady" and that the two spent time going over safety protocol and orientation. Richards eventually began flagging alone, and only hours after going solo, she was killed.

Defence lawyer Aaron Fox argued that the accident, while tragic, wasn't criminal.

Fox questioned how Richards was trained. He also asked RCMP Cpl. Jeff Burnett, an accident reconstructionist, about the signage around construction zones, and asked questions about the distance signs should be set up before construction.

If they're too far away, Fox stated, drivers may have the tendency to lose that attention. He noted there's provincial legislation for how far away signage can be posted to alert drivers of an impending construction zone.

Burnett estimated the vehicle was travelling between 82 and 99 km/h when it struck Richards. The speed limit was only 60 km/h.

Shortly after Richards' death, the province announced photo radar would be introduced in select construction zones.