As schools break up for the summer and families across the country load their cars up for their summer holidays, cries of 'are we nearly there yet?' will be chorused by over a million children

To help save parents' sanity, the AA has conducted research to find the best way of avoiding that breaking point. And the solution? Applying the 'break' rule every one hour 45 minutes, or every 93 miles.

The AA, the UK's largest motoring organisation, carried out research with over 1,300 parents, which showed that the 'nearly there' question will occur one hour, 40 minutes into the average summer holiday car journey of four hours and 28 minutes. It takes parents a further nine minutes to become irritated and another 30 minutes until they lose their temper entirely.

Based on their research, the AA has been able to calculate that parents will be able to travel, on average, 93 miles or for one hour and 45 minutes before becoming irritated by their children. The AA is therefore recommending that families take a 'nearly there' break at this stage in their journey.

Dr Pat Spungin, child psychologist and founder of the parenting website Raisingkids.co.uk, explains: 'The research shows how important it is to take regular breaks to prevent tempers fraying. A child's boredom threshold is lower than that of their parents', so it's key to compromise and find a comfortable breaking distance that suits everyone.'

Dr Spungin continues: 'It's easy in the confined space of the car to become irritated if the children are whining, but driving requires your full concentration. You need to keep the kids entertained in the car with stories, in-car games and singalongs so you don't get distracted.'

The AA's Patrol of the Year, Adam Ashmore, adds: 'Many AA patrols are parents as well so understand just how difficult driving with children in the car can be. We would always recommend planning your journey in advance, and allow plenty of extra time for breaks or delays. When you stop, make sure you get some fresh air and stretch your legs so that you are alert for the next part of your journey.

'As breakdowns can make journeys even longer and add to the pressure, we suggest that motorists make some simple checks to their vehicle before packing up and heading off. For example, checking tyre pressures, oil levels, and filling up your tank with fuel.'

Top tips for a stress-free summer journey include:

• Take regular breaks every hour and 45 minutes.
• Plan your route carefully and allow extra time for delays and breaks.
• Pre-plan in-car activities to keep children entertained. Get ideas for keeping the kids happy with our game tips for car trips and ideas for happy motoring with your toddler.
• Reading or colouring can bring on nausea, so stick to verbal games or games like I Spy which involve looking at distant objects.
• With very young children try to get your journey to coincide with their nap times.
• Avoiding heavy meals and processed foods before and during. Take healthy snacks and drinks so you don't fill up on junk.
• Adults can have a caffeinated drink to keep them awake, but swap children's fizzy drinks for water and natural fruit juices to keep them calm.
• Check vehicle oil and coolant levels and tyre pressure before setting off.
• Fill up your windscreen wash so you can have a bug-free windscreen.

Further hints and tips for back seat harmony this summer can be found at www.theaa.com