Couples get involved in most of their rows while in a car, with the arguments starting on average just 22 minutes into a journey, a new study has claimed.
Research by sporty Spanish car maker Seat showed as many as 36% of couples have more arguments in a car than anywhere else.
Sometimes an in-car argument can lead to serious consequences, with 10% of drivers confessing to separating from their partner after such a row.
The survey of 3,000 motorists showed that 71% of adults have argued with their partner about the quality of their driving.
Disagreements about directions and getting lost top the list of trigger points, with some 44% citing these as issues leading to a row.
Other reasons include driving too quickly (34%), driving too close to other cars (24%), backseat driving (20%), music/radio station choice (20%) and aggressive driving/road rage (17%).
An agitated driver is more likely to be involved in a collision on the road, which could adversely affect their car insurance policy.
Rob Taylor, national communications manager at Seat UK, said: "An agitated driver is much more likely to lose concentration and have a prang. And then you'll really have something to argue about."
© Press Association 2010