Revision - Keywords - Cambridge Accessible - A place or feature to which people can get to easily by some form of transport or by walking CBD -The central business district is the commercial and business centre of a town or city where land values are at their highest Congestion - A condition that occurs when user demand on a transportation system exceeds the capacity of the system at any point during the day Economically active people -The people who have jobs and are adding to the wealth of a place Employment structure - The division of jobs into primary, secondary, tertiary and quaternary sectors Greenbelt land -An area of land around a large urban area where the development of housing and industry is severely restricted and the countryside is protected for farming and recreation High-tech industry - An industry using advanced information technology and/or processes involving micro-electronics Pedestrianised street - An area or street where no cars or transport is permitted, people can walk safely Primary employment - An industry such as farming, fishing, forestry and mining. Raw material are extracted from the land or sea Quaternary employment - Jobs which provide information and expertise e.g. Market researcher and IT consultant Rural -An area of countryside Rural-urban fringe - A transition zone between the built-up area and the countryside Secondary employment - Jobs that involve manufacturing, or making things e.g. Car assembly, carpenters, builders and potters Tertiary employment -A job which provides a service e.g. Teacher, doctor, waiter or a shop assistant Tourism- An industry based on people’s which to travel and spend leisure time away from the home Urban - A built up area such as a town or city