Car patrol eliminated the neighborhood police officer. Police were pulled off neighborhood beats to fill cars. But motorized patrol — the cornerstone of urban policing — has no effect on crime rates, victimization, or public satisfaction. Lawrence Sherman was an early critic of telephone dispatch and motorized patrol, noted, "The rise of telephone dispatch transformed both the method and purpose of patrol. Instead of watching to prevent crime, motorized police patrol became a process of merely waiting to respond to crime."
That is from Peter Moskos’s Cop in the Hood: My Year Policing Baltimore’s Eastern District; here is my previous post on the book.