The body of laws in Oklahoma that make it punishable to drive while under the influence of alcohol or drugs is testimony to the accepted wisdom that it is a bad idea to take some substances like alcohol in excess before driving, and a bad idea to take other substances like illegal drugs at all. What you ingest or otherwise put into your body can result in catastrophic consequences not only for yourself, but also for others.

On the flip side of this metaphorical coin, there are some things that you can deprive yourself of that might also negatively affect your driving ability. One is sleep: drowsy driving can have you waking up wrapped around a tree or a telephone pole just as effectively as drunk driving can. You can also deprive yourself of paying proper attention to the road and to your surroundings if you allow yourself to become distracted behind the wheel, which is why texting while driving laws have become so much more prevalent with the widespread availability and use of smart phones, GPS devices and other electronics while underway in a motor vehicle.

Evidence has also emerged to suggest that water deprivation can have an adverse impact on your driving safety as if you had slaked your thirst with too much alcohol. In fact, the underlying study at Loughborough University in England has concluded that “driving while thirsty” can produce several of the same types of bad driving behaviors – delayed reaction times, impaired judgment, lane drifting and late braking – as though you had enough alcohol in your system to hit the .08 blood alcohol content level. In driving simulators, test subjects experienced more than twice the rate of what the study called “driving incidents” when they were even mildly dehydrated as when they were properly hydrated.

In some ways, dehydrated driving might be even more dangerous than drinking alcohol. Think of it this way: if you have a couple of drinks, you likely know that the alcohol could degrade your driving skill, so at least you are aware of the danger at some level. But most people probably do not equate being thirsty with having the same effect of being inebriated, so not only can they become more dangerous behind the wheel – they quite possibly have no idea of the danger.

Even having some knowledge of the risks inherent in dehydrated driving may not be enough, because of the temptation to underestimate its effects or to think that it is possible to “tough it out” instead of correcting the problem by taking in more fluids. Some drivers may fool themselves into believing that the supposed benefits of not taking in enough water, especially on longer trips (such as fewer restroom stops) outweighs any possible danger. Others may convince themselves that by drinking beverages like coffee or energy drinks they can at least offset the side-effects of dehydration. But the study suggests otherwise:

• Even when thirsty drivers were aware that their driving was being affected, and tried to “force” themselves to pay more attention through willpower, they were unable to do so.
• Coffee and other drinks containing significant amounts of sugar may temporarily contribute to being more alert, but they also tend to act as diuretics and can make the underlying problem of dehydration worse over time.

There is no law against dehydrated driving, and it is unlikely that any such law will ever be proposed at the state or federal level. But you should be aware that even though you may be able to “legally” drive just like you were under the influence of drugs or alcohol by not drinking enough water, it can still lead to an avoidable accident which in turn can still have legal consequences for you in both criminal and civil law settings. It is also very likely that the officer will mistake your symptoms and charge you with DUI.