A Tasmanian coroner says a fatal crash on the Midland Highway in 2020 could have been avoided if one of the drivers had not been high on cannabis.
WARNING: This story contains an image that may cause distress.
Three people died in October 2020 on the Midlands Highway when a car swerved to avoid solar panels that had come loose from a caravan travelling in the opposite direction.
The driver, AZ, and his family were travelling from Launceston to Hobart for a shopping trip so his seven-year-old son could spend his birthday money, coroner Simon Cooper noted.
The red Toyota Celica coupe he was driving swerved into the other lane and collided with a Holden Commodore behind the caravan.
AZ, his 15-year-old daughter, and his aunt — who was not wearing a seatbelt — were all killed instantly.
His seven-year-old son survived, suffering a broken elbow and leg.
The three people travelling in the Holden Commodore all suffered injuries.
In his report into the crash, Mr Cooper said an autopsy found that AZ had tetrahydrocannabinol (THC) — the principal psychoactive constituent of cannabis — in his body, while 8.4 grams of chopped cannabis was found in his boot.
Mr Cooper found AZ's car was travelling just above 90 kilometres per hour when he collided with the commodore, which had slowed to about 60 km/h.
He found AZ "overreacted" to the solar panels coming loose, with dashcam footage showing they flew well above his car.
"However, I am also satisfied that both his perception and reaction time were very likely to have been affected by the THC found in his body at autopsy.
"AZ should not have been driving. His inability to react appropriately to the solar panel because of the THC in his body was the principal reason, in my view, he, his 15-year-old daughter, and aunt died."
Adhesive on solar panels 'failed'
Mr Cooper found that the solar panel coming loose from the caravan was also a "significant factor" in the crash, noting there are no specific regulations governing how solar panels or similar accessories should be affixed to caravans and other similar vehicles.
The caravan was purchased by the owner, identified as IS, a few years before the crash.
He told police he arranged for the solar panels to be fitted onto it as an "aftermarket" addition after he purchased it, arranging for it to be installed by a qualified electrician.
The electrician told police he had installed the panels in accordance with the manufacturer's instructions and had installed them on other caravans in a similar way in the past.
Coroner Cooper found the adhesive used by the electrician to bond the panels to the roof failed, allowing them to blow free.
He also found strong winds at the time of the crash "no doubt" led to the panels being dislodged.
The Department of State Growth has tightened pre-registration checks of external equipment on caravans and other similar vehicles since the incident, while work has begun on national rules around aftermarket accessories.
