A police officer (or constable) is a sworn member of a police service with legal authority to enforce laws, maintain public order, investigate crimes, and make arrests. Officers undergo extensive training on law, procedures, use of force, and community relations before deployment. Ranks typically progress from constable through various supervisory and command levels to chief. Police officers may specialize in areas like traffic, investigations, community liaison, or emergency response. Municipal police services employ officers at various levels, with staffing significantly affecting police budgets. Officer conduct is governed by provincial police services acts and subject to oversight by police boards and civilian review bodies.