A transportation mode describes a type or means of transportation. The number of modes differs for different types of analysis, organizations, or areas. Often, transportation models or analysis will take into account only one mode (auto) or two modes (auto and transit). For other models or types of analysis, the list of modes can be very extensive, with a number of sub categories. Some of the modes used for analysis include: Auto; y Drive alone (also known as single occupancy vehicle (SOV)); y Auto as driver; y Auto as passenger; y Auto with others from the same household; y Auto with others from different households; y Taxi; y Motorcycle; Transit; y Bus; y Light rail; y Heavy rail (subway); y Commuter Rail; y Ferry; Active transport (modes of transport that are human-powered); y Walk; y Cycle; y Skateboard / rollerblade; y Wheeling (wheelchair, scooter). Some trips may include two or more modes. For example, a traveller may walk to a bus stop or drive to a park-and-ride. Three different terms are used to describe the relationship between the different modes. These are mode share, mode split, and mode shift. TPPT Environment Canada, TGreenhouse Gas Sources and Sinks: Frequently Asked QuestionsT, http://www.ec.gc.ca/pdb/ghg/about/FAQ_e.cfm,2006-11-18. TPPT Environment Canada, TInformation on Greenhouse Gas Sources and Sinks: Monitoring, Accounting and Reporting on Greenhouse Gases, HTU http://www.ec.gc.ca/pdb/ghg/ghg_home_e.cfmUTH, 2008-12-11. TPPT Environment Canada, TInformation on Greenhouse Gas Sources and Sinks: Factsheet 3 - TransportationT: 1990-2000, HTUhttp://www.ec.gc.ca/pdb/ghg/inventory_report/1990_00_factsheet/fs3_e.cfmUTH, 2009-02-04. TPPT European Platform on Mobility Management, General Information, http://www.epomm.org/index.phtml?Main_ID=820. (1) Mode share describes the percentage of all travellers using that mode. This is usually used when there are multiple modes and considers auto, transit, cycling, and walking. (2) Mode split normally describes the ratio of travellers between two or more modes (often auto and transit; although this also can be applied to other modal combinations) rather than among all travel modes. (3) Mode shift describes a change in travel patterns of a percentage of travellers from one mode to another over a given period of time. For example, if 100 of 100 employees in an office complex drove to work before the TDM initiative and 15 of 100 of those employees walked to work after the TDM initiative, the initiative has resulted in a mode shift of 15% from auto to walk mode. Mode share, split, and shift should always be qualified (which mode (share); which mode compared to which mode(s) (split); which original mode(s) to which new mode(s) (shift))