Four fatal shootings of livery car drivers in recent months have prompted hundreds to sign up for a program that allows the NYPD to randomly pull them over for safety checks. Drivers are given a decal to put on the back windshield of their black cars to let officers know they're participating. NYPD Deputy Commissioner Paul Browne says he hopes the program puts "would be criminals" on the defensive.

BROWNE: It's just being used as another possible deterrent that somebody getting into that cab who plans to rob it realizes it could be stopped at any time.

The New York State Federation of Taxi Drivers spokesman Fernando Mateo says drivers welcome the effort. He's working with counties outside the city to see if their police departments might institute a similar program. The most recent murder of a driver was Sunday night in Yonkers.