We all know that tempers can fray when you're at the wheel, but arguing when driving can be dangerous, writes motoring journalist Maria McCarthy.
What with dealing with traffic jams, tailgaters and drivers who don't indicate, driving is stressful enough.
But many of us don't only have to cope with road-related problems when we're at the wheel, but with strife from our other half aswell.
Research by the Health and Safety Executive in 2002 showed that if a person drives when stressed they run a much greater risk of being involved in a crash.
And a row with your partner can be a very stressful experience indeed.
Most couples will admit to arguing in the car. The topic might be related to driving, with the passenger criticising the driver's technique or decisions.
Or maybe the passenger thinks the driver is going to fast, is in the wrong lane or becomes irritated at their refusal to stop and ask directions.
Alternatively, the dispute might be about something more personal – money, home or family issues.
"People often find that they bring up relationship problems when they're in the car with their partner," says relationship counsellor Laura Marcus.
"This is because it can feel an unthreatening environment. It's not as if you've sat down to have a deep discussion, which can often make people feel pressured and uncomfortable.
"And there's also the fact that you're both facing forwards. I've noticed that people often find it easier to say what's on their mind when they're not facing the person concerned.
"If it's a relatively minor matter, some issues can actually be resolved when you're talking about them in the car.
"But problems arise when it's a more sensitive topic and the conversation becomes heated.
Arguments as a driving hazard
"This means that the driver is less likely to be able to give their full attention to the road.
"And whether you're negotiating busy city traffic or bombing down the motorway at 70mph, that can be dangerous," says Marcus.
Marcus adds that sometimes a passenger will raise thorny topics when they're out in the car as they know the driver will be restricted in how much they can react by the fact they've got to concentrate on the road.
Dr Nick Reed of the Transport Research Laboratory has been involved in research about driving and mobile phone use.
He found that drivers were more distracted by conversations they're having on their mobile phone, than one with a passenger in the car.
The passenger in the car can see tricky driving situations ahead, such as a difficult junction or a lorry pulling out unexpectedly, and pause the conversation - whereas someone on the other end of the phone can't.
So if you're annoyed with your partner it's best not to phone them and tell them so when they're driving – wait till they get home!
When it comes to avoiding arguments in the car, Marcus believes it's best to avoid commenting on your partner's driving.
"We all have our own styles and as long as there aren't safety issues involved, it's best to let whoever is at the wheel get on with it in their own way."