A new study from the journal Physiology & Behavior says that dehydrated drivers make approximately of the same number of driving errors as drivers with a BAC of 0.08%.
The study was conducted with healthy male drivers in their 20s in a driving simulator. The drivers were asked to perform a “prolonged and monotonous” driving task.
The study subjects made 101 driving errors when they were dehydrated as opposed to 47 when they were well hydrated. The dehydrated driving error rate was comparable to the error rate made by a driver at the legal limit (for most states) of 0.08% BAC.
Further, the dehydrated drivers had a higher mistake rate in the last half hour of the study than in the first.
While the study’s findings are dramatic, experts say the finding should be taken with a grain of salt because the scale of the study was small, female drivers did not participate, and simulated driving is not the same thing as real driving.