If you're going to be sitting in your car for hours, you'd better make sure your visibility is good, and that you're comfortable inside.
Can you see out?
Peering around a thick sludge of dead bugs that you can't clear off your windscreen is neither pleasant nor safe, so make sure your washer fluid is topped right up before you leave.
Don't be tempted to just top up the reservoir with tap water, though. This will progressively dilute the solution more and more and make it increasingly less effective at clearing the screen.
Check the condition of your wiper blades. Clean off any stuck-on gunk to help them wipe the windscreen better, and replace them if you detect any cracks.
Lastly, if the nozzles' aim isn't true, two minutes with a pin, a bit of twiddling with your nozzles, and you'll once again be spraying your windscreen rather than the unsuspecting people waiting at the bus stop.
If you normally use the car just for the quick commute to work, a long journey with kids and paraphernalia on board can put your car under sudden strain.
You don't want your family to end up sunburnt by the side of the motorway as steam rises from the engine - and dad's ears - so check the coolant levels when the car is cold and top them up if necessary.
You'll probably have to dilute some coolant before you add it, but no harder than topping up your washer reservoir and is essential basic maintenance.
Afterwards, clean off any splashes from the paintwork of your car to prevent paintwork damage, and wash your hands.
You'll also want to keep the family - as well as the car - running at the right temperature, and if your air-conditioning has been struggling to keep you cool on the commute, it's going to have no chance with more people on board and more work to do.
So, get down to the workshop to have the system checked over and re-gassed if necessary.