Daylight Savings Time (DST) was started to conserve fuel during WWI. It has stopped and started many times since then, but didn't become a permanent thing until the Universal Time Act of 1966. Even then, the government has tinkered with it many times.
Studies have shown that DST does very little to save energy costs during the summer. However, it has cost companies a lot of money to change their computers every time the timing DST has changed.There have been studies showing an increase in car accidents and heart attacks following the "spring forward" clock change.
DST really offers us zero benefits. There are many parts of the US that don't follow DST, as well as most of the world. This can also pose a problem for stock trading and other business purposes.
http://www.standardtime.com