A person released on their own recognizance does not have to post bail. Most first-time DUI charges are misdemeanors, so if there are no other serious charges, an officer will likely release the suspect without requiring them to post bail. This is not always the case, however.
DUI cases can quickly become more serious if the suspect has prior DUI convictions or other pending charges or if the accident caused serious injuries or death. In these cases, the suspect might have to appear before a judge to determine their release conditions.
The judge can require the defendant to post a bond with the court as a condition of release. Your attorney can challenge a too-high bond or other unfair release conditions.