Solar access:
Today  because of the large number of population, high rise buildings is going to increase. High rise and dense buildings could decrease the accessibility to sun light. According to King (2011 p2) lack of exposure to sunlight which has vitamin D ,for worker housing in19th century in Europe caused bone disease. Today sunlight should be provided to improve both human health and reduce the usage of non-renewable sources. Photovoltaic tiles, solar heat water and other solar power systems need enough sunlight to produce energy. Furthermore private and public open spaces and areas for drying cloths should have access to sun light (Waverley Development Control Plan 2010). For this reason urban design play important role to increase solar accessibility. Designing urban areas should be according to sun path of that area. In winters buildings should absorb sunlight by windows, but in summer shadow is more demanded for a building (King 2011 p1). Therefor sun path can determine the direction of buildings, blocks and streets. Before the construction of a building the shadow of it should be assess. In Sydney pavement needs at least 2 hour  sunlight in winters (King 2011 p7) Trees height and location in the street should be considered as well.
sources:
-http://www.academia.edu/4326214/Our_place_in_the_sun_urban_design_implications_of_solar_access_controls
-http://www.waverley.nsw.gov.au/__data/assets/pdf_file/0014/3470/Part_G2.pdf