An arrest warrant is a document that names a specific person and calls for him (or her) to be brought before the court. Generally arrest warrants are initiated by police and brought to a court official along with material that constitute probable cause, such as witness statements, physical evidence, and surveillance. If approved by a judge or magistrate, the person named can be arrested on the warrant and taken to a police station, booked, then held until his court appearance. At this appearance the judge decides if the suspect should be granted bail or held until trial.
A bench warrant (sometimes called an alias warrant) is another sort of arrest warrant that is generated by the court itself when an individual does not appear for a scheduled court date or has ignored a summons. A bench warrant may also be issued if a person skips bail or does not report to his probation or parole officer.
A misdemeanor warrant is a low-level summons, oftentimes to pay a fine. In some states police are not permitted to arrest and detain a person on a misdemeanor without an arrest warrant unless the officer witnessed a crime -- while those wanted on felonies can be arrested any time.
Many states have been overwhelmed with the number of warrants generated by police and the court system, and lack the manpower to execute them all. Another issue is how warrant information is disseminated among law enforcement officials, as well as to the public.
Boston issues about 2,300 criminal warrants a year, but Ferguson, Missouri was generating about 9,000 per year, resulting in a backlog of 16,000 outstanding warrants for the latter police and sheriff's departments to follow up on. Connecticut had 31,000 failure to appear warrants in 2015 and another 4,700 for violations of probation. This is not a new problem as many cities look to warrants and their associated fines for revenue: In 1999, California had 2.5 million outstanding arrest warrants, including over 2,000 for homicides. In 2001, Seattle tackled the city's backlog of 40,000 unserved warrants by purging 20,000 for misdemeanors that were at least 7 years old but retaining those for serious offenses.
While sheriff's departments are the primary arm of warrant enforcement for courts, local police who seek warrants for suspects often handle their own. A study of outstanding warrants showed that about 80 percent of local police and sheriff's departments serve warrants but a little more than 50 percent of state police do the same. Also, computerized access to court warrant information is not always available to police running a driver's license check during a traffic stop. It seems you're more likely to find out about an outstanding misdemeanor warrant when you try to renew your driver's license or when registering your dog at city hall.
State police are likely to only have information about felony warrants, which are usually entered in the National Crime Information Center database maintained by the F.B.I. Of course immigration officials will also have access to that information, so those who attempt to cross an international border (arrive in a U.S. airport from an international trip) may also be arrested on an outstanding warrant when their passport is checked.
If you suspect there's a warrant for your arrest, you should resolve it by calling the local courthouse for information. You may also search online for warrant information at local courts or state-level information.
Florida's search engine for outstanding warrants is located here: http://pas.fdle.state.fl.us/pas/restricted/PAS/person/WantedPersons.jsf
Minnesota generates lists of outstanding warrants. Check for your name here: http://www.co.rice.mn.us/DocumentCenter/View/1352
Maryland has a website for the state's most wanted: http://www.dpscs.state.md.us/publicinfo/DPP-violators/index.shtml
The city of Newport News, Virginia maintains a database of outstanding warrants at this site: https://www.nnva.gov/499/Active-Outstanding-Warrants