Police say charges will not be laid in a crash between a Mazda 3 and a Ford dump truck that killed Conestoga College nursing instructor Amy Stiles.

The crash happened Nov. 2 at 4:50 p.m. on County Road 21 near Fourth Line in Centre Wellington.

Stiles, 38, of Fergus, was pronounced dead at the scene.

The driver of the dump truck was taken to hospital with serious but non-life threatening injuries.

"The investigation has revealed that for unknown reasons the Mazda sedan crossed over the centre line into the path of the dump truck," police said in a release Tuesday.

The dump truck had no defects and police ruled out cellphone use by both drivers.

Co-ordinated PSW program

Conestoga College lowered its flags to half mast on Friday. The college said Stiles had worked there since August 2013 and served as the co-ordinator for the personal support worker program at Riverside Glen in Guelph.

The Ontario Public Service Employees Union (OPSEU) said in a statement Stiles was returning from a rally at Queen's Park to support striking college faculty.

OPSEU president Warren Thomas said in a statement.

"I am heartbroken for Amy's family, friends, colleagues and students," Thomas said. "I know all OPSEU members at the colleges, and throughout the union, have Amy in their thoughts."

Students 'feeling her passing'

A GoFundMe page set up to support the family said Stiles leaves behind three children, ages eight, 10 and 12, and her husband.

Her obituary said she was a graduate of Guelph Collegiate Vocational Institute and she received her bachelor in science degree in nursing from Ryerson University. She worked at Homewood Health Centre in Guelph, Grand River Hospital in Kitchener and Groves Hospital in Fergus. She also taught prenatal classes on a part time basis for Wellington-Dufferin-Guelph Public Health.

"Her students past and present are also keenly feeling her passing. The nursing community has lost a colleague," the obituary said.

A celebration of life is planned for Friday at the Fergus Sportsplex at 3 p.m. Visitation will take place before the celebration from 1 p.m. to 3 p.m.