Sydney Harbour Tunnel shuts after pigeon causes safety confusion

Authorities were left scratching their heads trying to figure out why overheight sensors were tripped, forcing the Sydney Harbour Tunnel to shut.

A brazen pigeon flying alongside a truck through Sydney Harbour Tunnel was the cause for a traffic jam, authorities confirmed.

The overheight sensors were tripped on Wednesday, resulting in the southbound lanes to be shut down for 20 minutes from 4.30pm on Wednesday.

Authorities originally thought it was a truck that tripped overheight truck sensors. Photo: Supplied

Initially, it was believed a semi-trailer was responsible for the overheight sensors going off.

But when authorities checked the CCTV, the truck measured a height of only 3.9m — well under the tunnel height clearance of 4.4m.

After scrolling through the CCTV footage to figure out what had happened, the confusion was quickly cleared up when a pigeon was spotted flying over the truck at the exact moment it passed under the detector.

A pigeon shut down the Sydney Harbour Tunnel for 20 minutes after tripping overheight truck sensors. Photo: Supplied

The pigeon flying over the top of a semi-trailer passing under the sensors caused the vehicle to register as overheight, triggering the sensors.

The truck had been forced to stop while authorities investigated but was finally allowed to leave an hour later.

NSW Roads Minister John Graham joked the pigeon would be reprimanded in an appropriate way.

“When the truck was measured as significantly under the height limit the incident became a mystery, and I want to thank the eagle-eyed tunnel operator who went back to the tape to discover the real culprit,” he said.

“On this occasion the pigeon will receive a warning rather than the usual 12 demerit points and six months off the roads — or above them in this case.”