Booking and charging

If it is determined after arrest that the person's blood alcohol concentration is not at or above the legal limit of .08, they will probably be released without any charges. One may, however, still be charged with driving under the influence of alcohol on the basis of driving symptoms, observed impairment, admissions and/or performance on the field sobriety tests. And if there is suspicion of drug usage, a blood or urine test is likely, or at least the testimony of a specially-trained officer called a Drug Recognition Expert (DRE). Assuming sufficient evidence of impaired driving from drugs, the arrestee may face charges of driving under the influence of drugs or the combined influence of alcohol and drugs.
Most of the time, the driver will either be kept in a holding cell (sometimes referred to as the "drunk tank") until they are deemed sober enough to be released on bail or on his "own recognizance" ("O.R."). A date to appear in court for an arraignment will be given to them. If they cannot make bail or is not granted O.R., they will be kept in jail to wait for the arraignment on remand.