Can Driving Dehydrated Be As Dangerous As Driving Drunk?

A study shows driving errors doubled (!) when driving dehydrated. This includes reduced concentration and alertness and judgment

Got water? If you are getting behind the wheel, that’s something you need to start to ask yourself — because driving dehydrated can have the same dangerous effects on a driver as driving drunk.

A study from Loughborough University in the U.K. and the European Hydration Institute found that a driver’s concentration, alertness and decision-making are reduced when not enough water is consumed beforehand.

It isn’t as surprising as you might first think. Hydration is critical to healthy brain function. Dehydration leads to immediate health problems, from headaches and fatigue to irritability and impaired short-term memory and judgment.

In other words, it makes sense.

Now that Michigan weather is getting hotter, it’s time to start thinking about drinking enough water — not just for your health, but also for your safety and for the safety of other drivers on the road.

Driving dehydrated led to double the errors in field study

The U.K. study consisted of two groups, each of which were told how much or how little to drink the day before the driving test. On the day of the test, each participant in the more hydrated group was given approximately 7 ounces of water once every hour, while the other group’s participants were given less than 1 ounce every hour (reaching mild dehydration status).

The two-hour driving test was split into four 30-minute sections. Both groups made more and more driving errors as the test progressed, such as drifting, car wheels crossing the rumble strip or lane line, and late braking.

However, the dehydrated group’s errors were consistently higher than in the hydrated groups — 101 compared to 47, respectively.

The dehydrated drivers also rated worse for feelings of thirst, throat dryness, hunger, concentration and alertness.

Further, the report said that the dehydrated group’s performance was comparable to driving with a blood alcohol concentration of 0.08% — the U.S. legal driving limit — or while sleep-deprived.

As the study’s leader, Loughborough Professor Ron Maughan, noted:

“We all deplore [drunk] driving, but we don’t usually think about the effects of other things that affect our driving skills, and one of those is not drinking and dehydration. There is no question that driving while incapable through drink or drugs increases the risk of accidents, but our findings highlight an unrecognized danger and suggest that drivers should be encouraged to make sure they are properly hydrated.”

Why is driving dehydrated dangerous?

Driving dehydrated is dangerous because it can impair your abilities in ways similar to alcohol. Research shows that dehydration can slow reaction times, reduce focus, and negatively affect decision-making, all of which are critical for safe driving. Physical symptoms like dizziness, headaches, and fatigue can further compromise your control of the vehicle. Since dehydration is often overlooked as a cause of driving impairment, it becomes a hidden danger that increases the risk of accidents without drivers even realizing they are impaired.

The dangers of driving dehydrated

Impaired judgement

Driving dehydrated can significantly affect the brain’s ability to make clear decisions. Even mild dehydration can slow reaction times, reduce focus, and impair judgment, leading to poor decision-making on the road. This increases the likelihood of mistakes, risky maneuvers, and accidents.

Delayed reaction times

Operating a vehicle while being insufficiently hydrated can delay reaction times, as your reflexes are slowed, making it difficult to brake or steer in time to avoid hazards. Reduced hydration also affects focus and cognitive processing, meaning you may respond more slowly to sudden stops, traffic signals, or unexpected obstacles, increasing the risk of accidents.

Reduced alertness

Driving dehydrated can reduce alertness, making it harder to stay focused on the road. You may experience increased fatigue, irritability, and mood changes, which can distract you from the task of driving. This decline in mental sharpness slows reaction times and awareness, raising the risk of accidents and unsafe driving conditions.

Physical impairment

Operating a vehicle while being insufficiently hydrated can delay can lead to physical impairment, as severe dehydration can cause dizziness, lightheadedness, weakness, and even blurred vision, making it difficult to control the vehicle. These symptoms reduce coordination and reflexes, increasing the risk of accidents and unsafe driving conditions.

How much water do I need to drink to stay hydrated

So how much fluid does an average adult need daily? The National Academy of Medicine says that an adequate intake of total beverages a day is approximately 13 cups for men and 9 cups for women.

That sounds like a lot to ingest mentally and physically, but you need not just stick to water to reach that quota. Any kind of liquid-based drink, such as juice and milk and even soup, can keep you hydrated. Tea and coffee are OK, too — the caffeine amount does not discount the fluid in them as we always heard when growing up. Even though the caffeine produces a slight diuretic effect, it still counts as hydration according to the National Research Council’s Food and Nutrition Board.

How to stay hydrated before and after a drive to stave off driving dehydrated

Staying properly hydrated is essential for safe driving, yet it’s often overlooked on long trips or busy days. Dehydration can reduce alertness, slow reaction times, and even cause physical impairment, all of which increase the risk of accidents. Fortunately, there are practical steps drivers can take to maintain hydration and stay sharp on the road. Here are some key tips to help you ensure you are properly hydrated:

Drink plenty of fluids

To avoid driving dehydrated, it’s important to make hydration a daily habit. Drink water and other fluids throughout the day, especially before setting off on a journey. Staying well-hydrated helps maintain focus, reaction time, and overall physical and mental performance, reducing the risk of accidents caused by dehydration.

Eat foods rich in water

Eating water-rich foods is an effective way to stay hydrated and prevent the risks of driving dehydrated. Incorporate fruits and vegetables with high water content, such as cucumbers, watermelon, oranges, strawberries, lettuce, and celery, into your meals and snacks before or during a trip. These foods not only provide hydration but also essential vitamins and minerals that help maintain energy, focus, and alertness behind the wheel.

Take a water bottle with you

Taking a water bottle with you is a simple yet effective way to keep you hydrated. Keep a spill-proof bottle of water in your car to sip on during your drive, ensuring you stay hydrated without waiting for scheduled stops. Having water within reach helps maintain focus, reaction times, and overall alertness, making your drive safer and more comfortable.

Plan your stops

To avoid driving dehydrated, it’s important to plan regular stops along your route. Don’t avoid drinking fluids to avoid needing the bathroom; instead, schedule stops to rehydrate and take a break. These breaks not only allow you to drink water and stretch your legs but also help maintain alertness, reduce fatigue, and ensure you stay safe behind the wheel.

Monitor your body’s signals

Monitoring your body’s signals is key to preventing dehydration while driving. Monitor your body’s signals by being aware of signs such as dry mouth, muscle cramps, dizziness, and dark-colored urine. Paying attention to these warning signs allows you to rehydrate promptly, maintain focus, and ensure safe driving conditions throughout your journey.

Preventing driving dehydrated starts with prioritizing hydration

Preventing dehydration while driving starts with prioritizing hydration, just as you would check that your vehicle is safe and your seatbelt is fastened. Make it a habit to drink enough water, take breaks every two hours on long drives, and stay attentive to your body. If you feel thirsty or notice symptoms of dehydration, pull over safely and drink water. Staying properly hydrated helps maintain focus, reaction times, and alertness, keeping both you and other drivers on the road safer.

Injured in a car accident? Call the attorneys at Michigan Auto Law now for a free consultation!

If you were injured in a car accident due to someone driving dehydrated, call Michigan Auto Law now (800) 968-1001 for a free consultation with an experienced car accident lawyer. There is no cost or obligation. You can also visit our contact page or use the chat feature on our website.

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