A Police Officer does need a warrant to arrest you for a DUI.  Ohio Revised Code (ORC) section 2935.03(C) provides the authority for it.

When there is reasonable ground to believe that a DUI has been committed a peace officer may stop or detain the person whom the officer has reasonable cause to believe was operating the motor vehicle and, after investigating the circumstances surrounding the operation of the vehicle, may arrest and detain the person. -(ORC) section 2935.03(C)

Compare this to ORC 2935.26 which says an office shall not arrest for a minor misdemeanor offense, like a traffic ticket, where the maximum penalty is $150 fine with no jail time.  There are a few exceptions which state that you can only be arrested for this when you require medical care, refuse to offer evidence of your identity, or refuse to sign the ticket.

It is very important for your attorney to identify the point of arrest.  This is where various constitutional rights attach.

Probable cause to arrest is only based on the actual knowledge of the officer at the point of arrest.  What other people know, and what he later discovers is irrelevant.

And remember, if you or a family member has been arrested for DUI in the Columbus, Ohio Area – give our office a call at 614-827-2000….24-hours a day, 7 days a week.