A lone pigeon has caused traffic chaos at peak hour on the Sydney Harbour Tunnel.
The bird was flying at great speeds over a truck and tripped the over height sensors about 4.25pm on Wednesday, causing the southbound lane to shut.
The truck, believed to have triggered the sensor, was stopped and reversed into the slip lane.
Traffic grew to about two kilometres and motorists were told to use the Harbour Bridge until the tunnel was reopened about 20 minutes later.
The truck remained with police at the scene for about an hour until it was cleared to leave.
One keen operator, however, noticed the 3.9 metre truck could not have triggered the over height sensor of 4.4 metres.
Scouring through the CCTV footage, the operator discovered the pigeon had flown over the truck and triggered the detection.
“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,” Roads Minister John Graham 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.”
