In most US and Canadian jurisdictions, passenger elevators are required to conform to the American Society of Mechanical Engineers' Standard A17.1, Safety Code for Elevators and Escalators. As of 2006, all states except Kansas, Mississippi, North Dakota, and South Dakota have adopted some version of ASME codes, though not necessarily the most recent. In Canada the document is the CAN/CSA B44 Safety Standard, which was harmonized with the US version in the 2000 edition.[citation needed] In addition, passenger elevators may be required to conform to the requirements of A17.3 for existing elevators where referenced by the local jurisdiction. Passenger elevators are tested using the ASME A17.2 Standard. The frequency of these tests is mandated by the local jurisdiction, which may be a town, city, state or provincial standard.