1. Double your travel time
However long you think you can do the trip in, count twice as long. Pushing on with tired, grumpy children (or grown-ups, for that matter) doesn't make for a relaxing trip. Factor in multiple rest times, pit stops and any spontaneous detours.
2. Pack snacks
Cheaper than service-station treats, and instantly deployable. Dry ones are better when it comes to kids - think crackers, not yoghurt - and an apple can while away a good 15 minutes (and keep mouths occupied). Snacking can also help with car sickness and any back-seat nausea.
3. Learn the power of a singalong
Be it kids nursery rhymes, or 80s power ballads, pull together a family-friendly Spotify list before you head off and listen to it often. That way, every time you hear a song from it, you'll be instantly transported your summer holidays.
4. Kick-start story-time
Start everyone talking about a happy time - maybe the last holiday you took, or the funniest thing that happened when you were all in the car last. Getting everyone going can take time, but once you're on a roll, it engages everyone.
5. Gamify the drive
No, we're not talking about a PlayStation - instead, employ the age-old driving games of your own childhood. I Spy for young kids is a good one. Any competition based "spotting" games - yellow cars, for instance, or depending on where you're road tripping, cows/horses/etc - can fire up siblings and have them engage with what's going on around them, rather than a device.