No it is actually "READ" as in have you read my last transmission.
You may also hear the expression "Read Direct" in situations where a unit has given a message to central to give to another unit, but since they heard the origional message they may call out "read direct" meaning there is no need for central to repeat the message to them.
I know a few PDs where cars can not go "CODE-3" unless authorized, but as long as I can remember, NYPD never tells the units how to respond (lights or sirens) and that is left up to the officer's discretion. There are department guidlines on what types of calls are emergencies and which aren't, but that's about it. They are after all just guidelines. Given the traffic in NY they may use light and sirens just to get back to the station for shift change. While not official policy this is tolerated because they need to get the next shift out on patrol and the can't wait for a hour for a unit stuck in traffic.