AN eighteen-year-old learner driver and his mum who shared a joint the night before driving through the Lang Lang checkpoint have been busted for alleged drug driving.

The learner driver and his 47-year-old mum who was the supervising driver both allegedly returned a positive result for cannabis when they were stopped by police at the Lang Lang checkpoint on Sunday, August 23.

Mum told police she thought the shared joint would be out of their systems.

Both tests will be sent to the lab and should they return a positive result, mum and son will lose their licence for six months.