In spite of the fact most drivers have complained about back seat drivers offering unwanted advice, a new study has found that sometimes it can be useful - but it often depends on whether that advice has been sought or not.
Back seat drivers can even help prevent serious accidents says Samuel Charlton, who is a professor of psychology at Waikato University and a co-author of research for the Automobile Association.
"There's this perception out there that passengers can be distracting, nagging and so-forth, but after the age of 24, having a passenger in your car actually decreases the chance you're going to have a crash."
He told Morning Report there are some things that passengers can do which can help drivers, but the way that it is done is important.
"Having a passenger look out the left hand window and telling you whether it's clear to go or not is very helpful."
He said providing directions in a timely fashion or unwrapping or handing the driver food can also be helpful.
But he said how it is done is important and it is useful to have a conversation about what the driver expects before the journey begins.
Just criticising the driver's driving is not very helpful, Charlton said.