A California has been charged with driving under the influence ... of caffeine.

Wait, what?

Given that Americans consume an average of 3.1 cups of coffee a day, it's unlikely he's the only driver on the road to have ever enjoyed such a seemingly innocent pick-me-up. So, how in the world could caffeine impair a driver’s capability behind the wheel?

According to NBC medical contributor Dr. John Torres, it wouldn't. “Studies have shown that caffeine actually helps ones driving abilities. The only way that it might have an effect is if a person overdoses on caffeine or uses it to cover fatigue and then it wears off,” Torres said.

One man's legal issues aside, caffeine does come with some surprising truths that many people may not know.

Light Roast Has More Caffeine Than Dark

When you go bean to bean, light roasts win in holding more caffeine. Why? The beans are exposed to less heat than dark blends, so more caffeine is not lost during the roasting process. The difference in caffeine between light and dark roasts isn’t enough for most to notice, but there are other ways to reduce caffeine, if that's what you're going for.

If you're trying to cut down, Torres suggests switching to cold brew coffees, since they contain less caffeine. You could also switch to tea, which cup for cup contains less than half the caffeine of coffee. Barring that, there's always decaf.

Caffeine Might Be More Effective in the Afternoon

Contrary to what many coffee aficionados believe, you don’t need a hit of caffeine as soon as you wake up. The reason behind this has to do with your cortisol levels.

Torres explains that your body’s cortisol levels peak around 20-30 minutes after you wake up in the morning. And by mixing these high levels of cortisol with caffeine can reduce the effectiveness of caffeine over time. It might be a pain, but try drinking that first cup of coffee in the middle of the day when your cortisol levels are lower.

It Could Improve Athletic Performance

Want to exercise harder and longer? Scientific studies have documented that caffeine increases athletic power and endurance. Caffeine directly effects muscle at the metabolic level by burning more fat, used as an energy source. This extra fuel gives you an energy boost and zest to work out. Keep in mind, overdoing the caffeine intake can decrease your performance. Aim to drink a cup about one hour before a workout since it takes time for the body to metabolize the caffeine.

Torres cautions that more caffeine is not necessarily better. Coffee is also a natural laxative, so drinking too many cups might cause an unexpected interruption during your workout.

Caffeine Temporarily Boosts Brain Power

Caffeine goes to the brain quickly and can affect it in a positive way. Studies have shown that caffeine can increase mental focus and concentration. Think of it as a natural stimulant. With moderate caffeine consumption, it can boost your ability to focus and increases alertness. However, overdoing it can cause unintended consequences.

Caffeine, especially in large quantities, can cause jitteriness and irritability, not something you want while taking a test you're already nervous about, Torres says.

If you drink too much, you may experience common symptoms like restlessness, irritability, and an upset stomach. For others, more serious side effects can include a fast or irregular heartbeat, anxiety and panic attacks. The key, Torres says, is moderation to get the benefits of caffeine without the side effects (or, in one man's case, a DUI).