It's been about 10 years since Alabama last used unmarked cars for traffic enforcement.
But the unmarked patrols resumed this week in North Alabama on Interstates 20 and 459, in Jefferson and Saint Clair Counties.
Two more unmarked cars will be based in Montgomery for use statewide. And more patrols will be added.
The cars based on I-10 and I-459 patrol an area East of Birmingham known as "Death Valley." It's called that because of the large number of fatal traffic accidents.