Amid claims that three out of four people in the UK could be dehydrated, the organisation claims it could be the cause of irritability and bad temper on the road.
Even a one-hour drive across a city can result in the loss of as much as half a litre of water, which needs to be replaced if drivers are to remain calm and comfortable.
And while caffeine-based drinks can fight off fatigue, the best solution to re-hydrate is water, the foundation claims. This is particularly important as soft drinks, tea and coffee may act as a diuretic, initially quenching thirst but actually leaving you more dehydrated than before having the drink, as they encourage the body to expel more water.
Edmund King, executive director of the RAC Foundation, said: 'Drinking plenty does not include alcohol, of course, but people should remember that 'taking more water with it' is an excellent motto for any journey.'