How fast can a police officer go without lights and siren?

the speed limit.
and even with lights and sirens, they, like all other emergency vehicles, are only supposed to exceed the speed limit by 10 miles per hour.

• • • • New York State Comments ****
        It may (and likely does) vary by state but in NY the "driver of an emergency vehicle, when involved in an emergency operation, may ... [e]xceed the maximum speed limits so long as he does not endanger life or property." Emergency vehicles doing so must utilize emergency lights and sirens *except* "for an authorized emergency vehicle operated as a police vehicle or bicycle". There is no limit as to how much in excess of the speed limit they may operate the vehicle and the exemptions apply to other vehicle and traffic laws as well as those specific to vehicle speed. [See NYS VTL 1104.]
        
        For most departments (if not all) policy also limits the legal exemptions but under law there is no limit to the speed driven if:
        1. it is an authorized emergency vehicle,
        2. it is involved in an emergency operation,
        3. it is operated as a police vehicle or bicycle, and
        4. the manner in which the vehicle is operated does not unreasonably or recklessly endanger life or property.
        
        In addition police are also allowed to operate in excess of the posted limit to calibrate their speedometers.
        
        As an aside most police officers I know also tend to drive just over the sped limit when traveling in a marked unit to avoid piling up a huge line of angry drivers behind them. :)
        **** End New York State Comments ****

First answer by ID1166759916. Last edit by AranMull. Contributor trust: 0 [recommend contributor]. Question popularity: 8 [recommend question]