Whether you've been charged with DUI/DWI or you're just confused about what these charges involve, it pays to understand the laws, penalties, and requirements associated with chemically-impaired driving. Here are four specific items you'll be want to bear in mind.

1. DUI and DWI Aren't Quite the Same Thing

You may hear the terms "DUI" and "DWI" bandied about as if they were interchangeable -- and sometimes they are, but not always. Technically, DUI stands for "driving under the influence," while DWI stands for "driving while intoxicated." That sounds like two different ways of saying the same thing, but there are can be subtle distinctions between the two. For example:

• While most states describe drunk driving as a DUI, others expressly brand this offense as a DWI instead, reserving DUI for other types of chemically-impaired driving. Texas, Arkansas, Nebraska, Missouri, and New Jersey are some of the states who follow this practice. 
• In states that charge both DUI and DWI, DUI is usually considered the lesser of the two evils and may lead to lighter penalties. Some states, however (notably New Jersey) place equal weight on both types of offenses.
• DUI offenses may not involve either alcohol or illegal narcotics. Many over-the-counter or prescribed medications can cause impaired driving. (That's one reason you should always read the directions and warnings on any medicines you take.)

2. The Arresting Officer Doesn't Have to Include Lesser Offenses

You may be pulled over for speeding or some other minor infraction and end up getting charged with DUI or DWI instead. Some drivers have the mistaken impression that because the arresting officer didn't also issue a speeding ticket or other citation, the omission will somehow indicate negligence on the officer's part and prompt a dismissal of the case.

Unfortunately, this isn't true. A police officer doesn't necessarily have to cite the original violation that caused him to pull a driver over. As long as the officer files the reason for his action in the official report, the judge won't question why the citation for the original offense was never issued. Criminal offenses such as driving under the influence trump civil offenses such as moving violations in these situations.

3. You May Need Special Insurance Following a Conviction

If you lose your driving privileges as the result of a DUI or DWI conviction, you may be required to purchase a special "certificate of insurance" known as a SR-22 before you can hit the road again. This type of insurance is designed to keep the DMV informed of your coverage (or lack thereof) at all times. Offenders are usually required to maintain an SR-22 certificate for three years, but some repeat offenders may be forced to keep up their coverage for life.

4. It's Easy to Go Over the Limit

If you are stopped for suspicion of DUI or DWI, the officer may subject you to tests to determine your blood alcohol content, or BAC. Every state in the U.S. currently frowns on a BAC of .08 -- a concentration of .08 percent alcohol in the bloodstream. But BAC  from a given number of drinks can vary widely depending on a person's body weight. A person who weights only 100 pounds, for instance, may show a BAC of .097 after just three drinks, while a 240-pounder might have to consume an entire six-pack of beer before going over the legal limit.

Since there's no way to guess at your BAC level with complete accuracy, you'll need to take precautions to make sure you haven't had too much to drink before you drive. Either carry a portable BAC unit with you or (better yet) simply let someone else do the driving.

As important as all these facts may be, the most important thing to remember about a DWI or DUI charge is that you don't want to get one! While penalties vary from state to state, they can and do involve stiff fines, loss of driving privileges and/or jail time. Play it safe, obey the law, and enjoy many more years of trouble-free driving.