It is not the law that a BAC breath sample must be given within 20 minutes of the arrest. The 20 minute observation period refers to a waiting period which is given to all persons (in some states it is 15 minutes) where the person who administers the BAC is supposed to observe the suspect for 20 minutes to ensure that he does not put anything into his mouth or hicup or belch. This wating period also allows any mouth alcohol to disipate. Without the appropriate waiting period, mouth alcohol can be present which will inflate the results of the BAC. You should contact a qualified DUI attorney in New York.
I agree with the first answer. I write only to point out most states have laws requiring the breath test be taken within 2-3 hours of the driving. If the breath test is not within the 2-3 hour period, then it may lose its presumption of reliability, or a presumption that it reflects your BAC level at the time you were driving. If the BAC test loses either of these presumptions, the prosecution may not be able to prove you guilty beyond a reasonable doubt.
Bottom line: You should consult with an experienced DUI attorney in your area. You can find an experienced DUI attorney in your area at the National College of DUI Defense: www.ncdd.com. Most initial consultations are free. So, you have nothing to lose!
Mr. Miyatovich is correct you may be conflating the 20 minute observation period with the .o8 or above per se statute's permissible inference (rebuttable presumption) that BAC while testing = BAC while driving. Check your local statute for what that inference is.
Edward J. Blum