Prepare Yourself for Sobriety Check Points: Know Your BAC

For those of you who want to be prepared for the occasional weekend evening sobriety check point on your way home from a restaurant or bar,  you'll want to check out this handy chart on blood alcohol concentration (BAC). The chart helps you figure out how many drinks you can safely have without going over the legal limit. The chart is only a guide -- a blood test is the only way to know for sure what your BAC is -- but you need some sort of yardstick to make decisions when you're out, and this is what's available.

Find your weight on the chart and move to the right on the chart one box for every drink you've had. When you go out, you'll want to plan to be under the legal limit, which in NJ is 0.08%. (See NJ Motor Vehicles Commission for details)

Remember: 1 drink equals

• one ounce of 100-proof liquor;
• one five-ounce glass of table wine; or 
• one 12-ounce bottle of regular beer

Don't forget that time affects the BAC number downward. The chart offers a relatively simple formula for figuring out the percent of alcohol "burned up" since your first drink. Simply subtract .015% from your BAC level on the chart for every hour that you've been drinking.

• If you're a 180 lb man and have had 5 drinks, the chart says you are over the legal limit at .104%. But if you have spent 4 hours chatting with friends while you drank those 5 drinks, you can subtract .060% (.015% x 4), which puts you back in the legal zone at .044%.
• If you're a woman at 130 lbs and have had 3 drinks, the chart says you're over the limit at .087%. If you spent 2 hours having those drinks, you can subtract .030% (.015% X 2) from your number, which puts you under the legal limit at .057%.