AN incident involving two trucks has south bound traffic backed up 10 kilometres on the Hume Highway.
Police said the incident occurred at 1.30pm today (Friday) when a truck travelling up Catherine Hill towards Mittagong experienced mechanical problems.
Bowral Police Sergeant Darren Farr said a front to rear collision happened between two trucks travelling southbound on the Hume Highway.
Sergeant Farr said it is believed the first truck was travelling slowly because of mechanical difficulties.
The driver of the second truck has now been airlifted to hospital.
His condition is unknown.
One lane is still blocked but Sergeant Farr said it should open soon.
The RTA handed out water to people stuck in traffic.