A blood alcohol calculator at the finger tips: Thousands in Colorado will have access to one this New Year's Eve and likely will put it to use. Some experts are urging people to use the programs with some caution.

The final, end of the year party is about to begin.

"It's New Years. You're going to be out anyway," said Larry, a Colorado Springs resident.

In the year of the iPhone application, some programs claim they can spell out danger for a driver considering getting behind the wheel.

"I know how you feel versus where you're really at would deter a lot of people. I know it would me," Larry said.

The Colorado Department of Transportation's application asks “R U Buzzed?” The program allows the user to select their weight, age, and the number of drinks they’ve had over a period of time. It then calculates an estimated blood alcohol content.

It's been downloaded by more than 35,000 people, coming up with answers based on the realistic input of how the party is going.

"Their thought is, if you plug in that data, the phone is going to tell you you've had too much to drink,” said attorney David McDivitt.

McDivitt recognizes the application as a reasonable guide, but not a precise instrument for driving decisions.

"No phone, and no App can tell you you've had too much to safely drive," he said.

To avoid much of the risk, for the second year, the McDivitt law firm is offering to pick up the tab for Colorado Springs partiers who call for a Yellow Cab home this New Year's Eve.

"Maybe we'll get a few fewer calls, but that's better if we know the roads are safer for people," McDivitt said.

Another bonus to the R U Buzzed? App provides a direct link to a cab company in the area just by tapping the screen.

To take advantage of the McDivitt Law Firm’s offer of a free cab home, all the Yellow Cab driver has to hear is"charge it to McDivitt.” The law firm will pick up the tab.

The service will be running from 10 p.m. to 4 a.m. on New Year's Night in Colorado Springs.