The truck driver who struck and killed cyclist Nusrat Jahan in September 2016 failed to obey a traffic signal before the collision, an Ottawa police expert testified at the man's trial Wednesday.

Steven Conley has pleaded not guilty to criminal negligence causing death and dangerous driving causing death.

Jahan, 23, was cycling to school in the dedicated cycling lane on Laurier Avenue W. just before 8 a.m. on Sept. 1, 2016, when Conley's truck struck her while turning right onto Lyon Street.

Jahan had arrived in Canada from Bangladesh with her family three years earlier.

Det.-Const. Alain Boucher, a collision reconstructionist, took over the case from another officer almost two months after the incident.

Boucher told court he examined City of Ottawa traffic video captured by a camera about a block west of the intersection of Laurier Avenue W. and Lyon Street.

The images clearly show Conley beginning to turn right when the eastbound traffic signal turned from red to a forward green arrow, Boucher testified. Under Ontario's Highway Traffic Act, that constitutes an illegal turn.

"Had Conley waited for the solid green light, then the collision would not have occurred," Boucher wrote in his report.

Meanwhile Jahan had begun cycling through the intersection when the green arrow appeared, and had right of way at that time.

The photographs also show a traffic sign next to the cycling lane warning motorists to give priority to cyclists.

As part of his investigation, Boucher also attempted to reenact the collision in early November 2016.

A cyclist posed as Jahan and a similar truck to Conley's was driven by a city worker who wore a camera strapped to his forehead. On the video, which was played in court, the driver can be heard saying he could see the cyclist from the shoulders up when he was stopped at the intersection.

Boucher's report concluded the driver could clearly see the cyclist, but he was forced to retract that conclusion on the stand because the city had reconfigured the stop lines on Laurier Avenue W. after Jahan's death.

In some cases, stop lines for bikes in segregated cycling lanes were shifted forward and the stop line for traffic was moved back to make cyclists more visible.

​Boucher testified he adjusted the vehicle stop line back to where it was at the time of the collision, but failed to account for the new position of the cyclist's stop line. The officer told the court he realized his mistake last week.

"I didn't pay enough attention to the cyclist's stop line," he testified.

Boucher told Crown prosecutor John Ramsay that because of that, his conclusion from the reenactment may have been different.

"The driver may or may not have seen the cyclist if we had the stop line in the right spot," said Boucher. "It would have been difficult for the driver to see the cyclist."

The trial continues Thursday.