What is Robert?

>What is Robert?
CPD Phonetic Alphabet:

Adam
Boy
Charles
David
Frank
George
Henry
Ida
John
King
Lincoln
Mary
Nora
Ocean
Paul
R O B E R T
Xray
Yankee

In the Chicago Police Department (CPD), the number of a police car ends in "R" if that car belongs to the night shift.
Car #1488R will be called over the radio as "One-Four-Eight-Eight-Robert."
Also, a 'Code R' (called over the radio as simply "Robert") is CPD radio code for an officer-made arrest.
Every time an officer makes an arrest, calls out their car number during the night shift or has their car number called out by dispatch during the night shift, the word "Robert" will be spoken.