A modular law enforcement baton having at least two useful functions disposed at a first end and a second end is described. The police baton comprises a unit comprising a handle and an elongated member connected to the handle. A first portion of the unit comprises a battery module and a battery for completing a first useful task. A second portion of the unit comprises a module for completing a second useful task. Useful tasks include but are not limited to providing light, providing pepper spray, optical scanning, measuring vehicular speed, measuring human blood alcohol levels, etc. The police baton may further comprises at least one of an accelerometer, a force gauge, and a strain gauge positioned within the unit and capable of measuring at least one of the acceleration, the force, and the strain to which a police baton is typically subject. The police baton may further comprise an automated processor, memory, persistent storage, a radio.