Believe it or not, if you take out your driver's license and look at the bottom of it, you basically signed your license stating that, by signing this, you're agreeing that you must take sobriety tests if called upon to do so. Otherwise, your license is going to be revoked temporarily and you're going to be arrested if you don't take the field sobriety test. That being said, you probably shouldn't take them if you feel like you're intoxicated and you're not going to pass them, because that only will provide the state with further evidence to prove the charge against you. It's kind of a trade-off, but it's one that has to be made on a case-by-case basis. Generally, I would say if you know you've been drinking, don't take the field sobriety test.