Even mild dehydration can impair driving performance to the same level as low-level alcohol intoxication.
Charlotte Metcalf of the South African National Bottled Water Association (SANBWA) warns, as millions of South Africans are heading to holiday destinations, to be aware of dehydration when they prepare for long road trips.
She says emerging global research shows a surprising and often overlooked link between dehydration and road safety.
International studies conducted at Loughborough University, the University of Connecticut, and several European transport institutes have repeatedly shown that drivers who are just 1% to 2% dehydrated experience slower reaction times, reduced concentration, poor judgement and increased weaving across lanes.
In controlled simulations, researchers found that mildly dehydrated drivers made as many driving errors as those with a blood alcohol content of 0.08%, the legal limit in many countries. Errors ranged from late braking to drifting, delayed hazard recognition and difficulty maintaining consistent speed.
In a high-speed environment, these subtle impairments can have serious consequences.
Metcalf says this science is especially relevant for South Africa, where long road trips, high temperatures and congested holiday routes create ideal conditions for dehydration to set in unnoticed.
“We think of dehydration as something that happens when you exercise, but it also affects people sitting still in a car for hours. The heat trapped in vehicles, caffeine intake, and the stress of driving all accelerate fluid loss. Many motorists treat hydration as optional, when in reality it directly affects alertness, decision-making and reaction time.”
The risk is heightened for children, older adults and people travelling with pre-existing medical conditions. Symptoms of dehydration include headaches, dizziness, irritability, fatigue and difficulty focusing; and this can emerge long before a person feels thirsty. In a high-speed environment, these subtle impairments can have serious consequences.
The SANBWA’s guidance to drivers this festive season is simple: Hydrate before you feel thirsty; and keep safe, clean drinking water in the vehicle throughout your journey. Consistent small sips are more effective than infrequent large drinks, and water remains the safest, fastest way to rehydrate without adding sugar or stimulants.
Pack enough water for the trip, take rest breaks every two hours, and drink steadily throughout the journey.
Because hydration is also a question of safety and purity, the SANBWA encourages travellers to choose bottled water that carries the SANBWA logo. This mark signals that the water is sourced, bottled and tested according to the strictest safety, microbiological and environmental standards in South Africa.
For consumers on the road, often far from their usual water supply, the logo is an easy way to ensure confidence in what they are drinking.
The SANBWA also stresses the environmental responsibility that comes with increased holiday consumption. Travellers are urged to recycle every bottle and avoid littering along highways, rest stops and nature reserves. PET bottles of SANBWA members are 100% recyclable and compatible with South Africa’s well-established mechanical recycling system. Keeping them out of the environment and in the recycling stream helps reduce pollution and supports the country’s circular plastic economy.
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As families gear up for December journeys, the SANBWA reminds motorists to build hydration into their safety routine: Pack enough water for the trip, take rest breaks every two hours, and drink steadily throughout the journey.
“Staying alert isn’t only about avoiding alcohol or fatigue. Hydration is a proven, science-backed part of road safety. A few sips of water at the right time can save lives,” Metcalf stresses.
