True, the 5th Amendment gives us all the right to not incriminate ourselves. But, a 1966 SCOTUS decision (Schmerber v. California) held that a state could force a blood-alcohol test on a driver of a motor vehicle without violating their 5th Amendment rights. That case was upheld and expanded in an '82 ruling (South Dakota v. Neville) which decided that not only could blood be drawn, but that licenses could be revoked for refusing such a blood test.
Tiger skated with respect to the immediate aftermath of the accident. Almost anyone else in a similar position, after being evaluated by LE, would have been asked to submit to a BAC test. Remember, Tiger's wife told the EMTs that he had been taking Viodin and Ambien, and had been drinking earlier in the day - all reasonable cause for LE to suspect impaired driving. But, those questions weren't asked by LE until the following day, when it was too late.