There is no simplistic answer for your question.
In New York, its probably better for a first offender to blow into the device UNLESS you believe you're well over the legal limit. That's because if you refuse to take the breath test, you will be subject to an Administrative Revocation of your Driver's License by the DMV. This is usually worse than having your license Suspended for 90 days if you've blown into the device and been found over the limit. Of course, if you're too far over the limit, the District Attorney may then not wish to offer you a plea bargain and could then use the test results to prove you were intoxicated while driving.
All in all, if its your first time DWI stop, its probably, on balance, better to blow into the device than not.
If you want to try the case and take a shot at trial, then it would serve you to refuse to blow and take it to trial. The greatest benefit of not blowing is the prosecutor then has no verifiable proof of your intoxication. However, he/she can still use the Police Officer's testimony to try to prove your intoxication independently of any breath test and that can often be acceptable evidence for a jury to rely upon.
Therefore, if its not your first time DWI charge and you may be charged with a FELONY, it would probably be best to NOT take the breath test. They will have less proof of intoxication in that scenario.
One added concern is if you are convicted of DWI or DWAI in most New York Counties, you will also be subject to losing the vehicle you were driving. This is another reason you may not want to simply take a plea bargain to a lesser crime or violation. If you win at trial, your car is no longer in jeopardy.
In most states, including Arizona where I practice, the penalty for refusing or failing to complete a test of your breath, blood, or other bodily substance to determine alcohol content is suspension of your driving privileges for 1 year. On the other hand, in many cases, the results of that breath or blood test will be the most important and most incriminating piece of evidence that the State will have to use against you at trial. I usually advise my clients that, if they firmly believe that the test result will show them to be over the legal limit of .08 BAC, then they should refuse the breath or blood test. This is especially true for clients who have prior DUI's (in the last 5 to 7 years) because the penalties are greatly increased in those situations.
Furthermore, I always advise clients that they should refuse any test conducted at the scene (roadside tests such as walking, standing, counting, alphabet, eye tests). Many of these tests are not scientifically valid indicators of alcohol impairment, and they are designed for you to fail. You have every right to refuse these tests with no penalty. This applies to the portable hand-held breath testing devices used by police officers in the field. You will not suffer a penalty for refusing any test, unless you are first informed of the potential penalty in advance of your refusal.
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