If you're worried you've had too many drinks to get behind the wheel on New Year's Eve, fear not: There's an app for that.

Just reach for your iPhone, because several apps are now available to tell someone when they've reached their legal limit.

"R-U-Buzzed," a free application released Dec. 2 from the Colorado Department of Transportation, allows you to quickly determine your blood alcohol level. Simply spin the wheel to your weight, how many drinks you've had and the amount of time you've been drinking and the app will tell you if you're safe to drive.

Additionally, the app allows the user to contact a cab, although this feature only searches for cabs within Colorado. The app will guide users in other states to links for cabs in their areas. Of course, the app doesn't provide an exact, scientific reading because it doesn't take into account factors such as specific drink variations, an individual's metabolism or how much the person has had to eat.

"We just wanted this to be used as a guide because most people don't realize that with just a few drinks your ability to drive may be hampered," said Stacey Stegman, spokeswoman for the Colorado Department of Transportation. "It will hopefully make people err on the side of caution."

One app that claims to provide more precision in determining users' blood alcohol level is "Last Call" from Avvo.com, a website that helps people find and select lawyers.

Last Call requires the user to input more detailed information on the size and type of drinks consumed, and tracks the amount of time drinking automatically.

Avvo CEO and founder Mark Britton says that when it comes to deciding whether to get behind the wheel, "The more precision that Last Call can bring to this decision the better."

Last Call also helps the user find a local cab, and a local lawyer "if they have made some really bad decisions," Britton said.

Some anti-drunken-driving advocacy groups have reservations about these applications.

"We are not against the application but we believe it should be stressed that people should determine, before they start drinking, a sober, safe ride home," said Mothers Against Drunk Driving CEO Charles Hurley.

MADD believes that only drivers with a blood alcohol level above 0.08% should face arrest, but the organization believes the most responsible decision is to not drive after the consumption of any amount of alcohol.

"Measures such as the iPhone application have some merit but it should be stressed the best practice is don't drink and drive. Period," said Hurley.

Britton says it is unrealistic to expect people not to have anything to drink before driving when they are celebrating the holidays away from home.

"There is not an iPhone app that prevents people from drinking," Britton said. "The most responsible thing we can do is give them the tools to monitor their drinking."

"I think MADD feels like we do. Nobody should look at this as an absolute to use to decide to get behind the wheel," Stegman said of R-U-Buzzed.

The real value of the application lies in keeping attention focused on the problem of drunken-driving.

"We've had to get more and more creative each year to keep drinking and driving at a high level of public awareness," said Stegman.

By Will Cummings/Drive On