In any drunk driving prosecution, the arresting officer must be able to show that he or she had probable cause to stop the driver of a motor vehicle in order to be allowed to testify regarding evidence of intoxication found after the stop. Without sufficient probable cause, any evidence obtained as a result of the stop, must be suppressed. That means that the information cannot be used as proof of being under the influence. If there is a determination that there was probable cause for the stop, the prosecution must then justify any investigatory detention. If the facts presented are insufficient to justify detaining the driver after the initial stop, then a motion to suppress all subsequently-obtained evidence should be made. If the motion to suppress is successful, all evidence other than observations and statements made during the brief stop will be ruled in-admissible at trial. Even if there is probable cause to detain the driver for a field investigation (field sobriety tests and brief questioning) there must be a considerably greater amount of evidence of intoxication to warrant an arrest. (There must also exist the authority to arrest, involving the question of whether the offense was committed in the officer's presence.) Without this greater evidence of intoxication, evidence obtained after the arrest (which usually includes the blood-alcohol test or refusal) is subject to suppression.
In the OVI/ DUI case the prosecution must establish an increasing amount of of evidence at each of the three stages of activity ie 1. the stop, 2. detention, and 3. arrest. Lacking the sufficient amount of evidence at any stage can result in suppression of all evidence obtained thereafter.
There are, of course, thousands of federal and Ohio State cases interpreting, in general terms, what constitutes sufficient probable cause to justify stopping, detaining, and arresting a citizen. This authority should be used in a motion to suppress. Keep in mind that a "double standard" appears to exist when it comes to drunk driving situations. Because of public concern and pressure, both the trial and appellate courts often prove more willing to find probable cause in OVI/DUI cases than in other types of offenses.