these devices are very good but they are not fool proof. they can read your prints wrong and fail to identify you. the new yorker magazine had a good article on this about 3 years ago Original Article Portable fingerprint device assists in DUI crackdown IDs essential, say police, judges and prosecutors Senta Scarborough The Arizona Republic Dec. 14, 2005 12:00 AM MESA - Police are taking fingerprinting to the streets to help better identify drunken-driving suspects and speed up court cases. Starting this month, drunken-driving suspects arrested in the annual police holiday crackdown are being fingerprinted using a portable machine that is the size of a suitcase and costs about $45,000. The process, a first in Arizona, takes about 15 minutes. In Mesa, most DUI suspects are cited and released after police on the street take a single ink fingerprint made on the citation. Police make sure the person has a ride home or will call a cab, if needed. But the Mesa Police Department doesn't have enough room to hold all DUI suspects because it would overcrowd the jail, said Mesa traffic unit motor officer Brad Withrow.The portable LiveScan's computer, keyboard and scanner allow an officer to record all 10 of a suspect's prints. The 10-print scan provides more detailed and accurate identification. Withrow, who spearheaded the project, said getting the prints right away can make a difference because some drunken-driving suspects will provide a false name or license to avoid prosecution. Recently, a Mexican national who used 10 aliases in separate drunken-driving cases, including some in Mesa, pleaded guilty and was sentenced to 12 years in prison, Withrow said. "These people will use two or three names and have two or three DUIs pending at one time," Withrow said. "With this, you have a positive identification of the individual you arrest that night." The portable machine will also save court time because if the one-print method is used on the street, judges typically order a full set of prints before a trial. "The idea here is identify the person right at arrest and eliminate the court appearance, and there is no question about identification hearings," Withrow said. "It is locking that person with that arrest." Mesa police forensic identification technician Gary Mollencopf said getting the identification at the time of arrest helps speed up the process of entering the information into databases. If the suspect's fingerprints are in the database, police can quickly find prior criminal history or determine if a person is using a false name. "The quicker you get the fingerprint in the system, the quicker you know who (you) have, and from a justice standpoint that is the real value," Mesa City Prosecutor John Pombier said. "We don't want people taking advantage of the system. We want to hook up the right conviction to the right people and the right charges." Mesa Municipal Court Presiding Judge Matt Tafoya said the process will help expedite cases. The court handles about 2,500 DUI cases each year, Tafoya said. "We love it because you have definitely identified the person cited," he said. "It eliminates the identification issue." A version of this story appeared in the Mesa Community edition.