This is the dramatic moment a truck driver sent sparks flying inside Sydney's airport tunnel this morning, setting off the sprinklers and causing traffic chaos.
A motorist filmed as the apparently unaware trucker scraped against the walls and smashed into the sprinkler system, creating plumes of acrid smoke.
The crash at 6.45am caused hours of congestion for commuters heading south towards the airport, with one lane closed because it was flooded.
At one stage there were 4km queues near the tunnel, but traffic has since eased.
The flow of water from the broken sprinklers was so severe that motorists were forced to use their wipers as they inched through the tunnel earlier this morning.
Traffic officials told motorists to 'expect significant delays'.
The sprinklers were switched off shortly after the crash and no more water is leaking into the tunnel.
John Sunde was cycling through the tunnel when the truck hit the sprinklers.
He posted a picture of the aftermath on Instagram, adding that the malfunctioning sprinklers had given him an 'early shower'.