If you're been stopped by a police officer for speeding, running a stop sign or having a burned out head light and he or she suspects that you've been drinking (whether or not that is true), you may be asked to test a breathalyzer test. Such tests measure a person's blood alcohol concentration (BAC) to see if it's above or below your state's legal limit.
How breathalyzers work
Invented in Indiana in 1954, the breathalyzer works by measuring the alcohol in the air sacs of the lungs. When a person drinks alcohol, a certain amount of the alcohol passes into the lungs as it passes through your mouth. Since there is a direct correlation between the amount of alcohol in these air sacs and the alcohol in the blood, the result of a person blowing into a breathalyzer can be used to determine a person's BAC without a blood or urine test. Obviously, breath tests are better suited for the field than blood or urine tests for alcohol consumption. The legal, upper limit for alcohol consumption in most states is 0.08 grams per 100 ml of blood, although a few states still have a 0.10 limit. If you hold a commercial driving license (even if you're not working), the level limit is 0.04 in most states.
Your rights and breathalyzers
If you've been asked by a law enforcement officer to take a breathalyzer test, you have the right to refuse such a test. The consequence of your refusal varies by state. In some states, you will have your license suspended for a period of time for refusing the test. The choice whether to take a breathalyzer test can be a difficult one, but refusing may still be the best course of action. On one hand, there are penalties associated with refusing the test; on the other hand, obtaining a DWI conviction is much more difficult for the court when there are no breathalyzer results.
If you're arrested on a DWI charge, you may be tempted to face the judge on your own without a lawyer present. However, this is rarely a good (or even cost-effective) idea. The penalties for DWI offenses vary by state, but virtually always include a large fine and possible jail time. A good DWI defense lawyer knows the laws in your area as well as the right people to deal with in the court system to help minimize the cost of this charge to you in time, money and reputation.