The defence presented its case in Supreme Court on Thursday in Summerside, where Gregory Collicutt is on trial for dangerous driving causing death.
Defence lawyer Peter Ghiz argued the RCMP were lax in their investigation of the deadly crash that left one woman dead.
He said a mechanical problem with the gas pedal may have caused Collicutt's car to accelerate unintentionally and that RCMP failed to investigate that possibility.
Ghiz also said that Collicutt was wearing rubber boots that day and that the cruise control was turned on but police didn't investigate whether those could be connected to the crash.
"For someone to shoot that stop sign at 11:18 in the morning would be tantamount to insane. It would be an attempt at suicide," Ghiz told the jury.
"You have to eliminate the possibility that the vehicle did not malfunction."
Ghiz said there was no clear timeline to show when the event data recorder was removed from Collicutt's car, and who had access to it. The Crown entered the recorder yesterday and a police witness testified that it showed Collicutt's car was driving between 95 to 117 km/hr and that the brakes were not applied.
The defence called Jason Young, a mechanical and biomedical engineer and traffic collision reconstructionist to testify about the series of events that could have led to the collision.
"This accident was likely due to pedal misapplication. He was pressing the gas pedal, thinking it was the brake pedal," he said.
Young testified there were factors at play that are common in cases of pedal misapplication.
He said Collicutt's unfamiliarity with the vehicle, unusual footwear, the fact he was transitioning from cruise control, and the pedal design of the vehicle all contributed to the crash.
Young agreed with police findings, as recorded by the event data recorder, and said Collicutt's high speed and lack of braking is consistent with other well-documented cases of gas pedal misapplication.
Young also said that he had been in two similar collisions as a passenger and said that pedal misapplication often drastically affects the driver's state of mind.
"You're on the gas and you think it's a brake and you don't know," he said.
"It's a mental state of panic that does not allow you to understand what's going on."
Ghiz told the jury Collicutt, 27, has a clean driving record, and suffered serious injuries in the crash, including a broken leg, that have left him partially disabled.
"He is permanently injured both physically and mentally," Ghiz said.
67-year-old Dorothy Mayhew died in the crash two years ago in Central Bedeque.
The defence finished presenting its evidence to the jury late Thursday afternoon.
Defence and Crown lawyers will present their closing arguments to the jury on Monday.
Then it will be up to the jury to deliberate on the evidence and come up with a verdict.
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