1. Overcrowding.
2. Transportation.
3. Safety.
Overcrowding:
Population rate is different from a city to another due many factors, however; its growth continues to increase day by day which creates overcrowding. According to the urban planner Le Corbusier, in his dream city that mainly contains skyscrapers created a population density and increased the issue of overcrowding, on the other hand these high buildings occupy only 12% of the land and 88% is open space which can be used for parks and new constructions. Overcrowding problems in big cities attracted Howard. First, he suggested building new cities in the countryside, second, he thought of making these new cities equipped with Schools, Industrial work places and houses.
Transportation:
Transportation in big cities has always been a big issue that governments needed to solve and it is one of the challenges that face urban planners. Jamie Lerner which was an urban planner in Curitiba, he closed the roads and built the first pedestrian mall. He also created new systems for buses which come every sixty seconds during peak hours. Lerner designed arterial traffic paths, which are three roads, one of them is a bus lane only and it carries around two million passengers a day using these buses. (As cited in Journeyman Pictures, 2006)
Safety: With the growth of urban cities population, the number of crimes increased as well, which made Jane Jacob give solutions on how to avoid the dangers and crimes, and she also believed that there had to be eyes on the street. There should be people watching the inhabitants of the neighbourhoods, malls, parks and places where mostly crimes happen, to stop them doing their crimes. Williams (2010) stated that the Garden city, Radiant city and City Beautiful separated the city functions, and left parts of the city empty at different times of the day, which increases the number of property