Supporting details help!!

The major details of the passage are:

“Factors that contributed to suburbanization”.

Explanation:

The passage presented gives information about why and how people started to live far away from their place of work when initially they would live nearby to their workplace.  

Living near their workplace used to make it feasible for them to commute as there were limited government facilities available at one time. But eventually, with progress and better facilities and infrastructure being developed, the people started to live far away from the work place and preferred to drive to work.

This also led to the concentrated area becoming the commercial area of work and business.