The scanner automatically reads license plates of passing cars and checks them against a police database. In the first week the scanner was on board Sherwood's car, he estimates he cleared six hundred outstanding warrants, including warrants for people who owed the city money on unpaid fines.
"You're able to pinpoint them without having to do as much of the digging," Sherwood said.
In tight budget times, the expensive scanners may turn out to be a good investment. They cost about $25,000 a piece. Lewisville has installed them in three cars, using grant money and money from the city's municipal court system. The city is betting it may be able to haul in enough deadbeats on unpaid tickets, that the scanners will eventually pay for themselves.
In one year, the plate scanners have also helped police recover 14 stolen cars, capture robbery suspects and hit-and-run suspects just by driving and scanning.
"It is a very, very valuable tool," Sherwood said.