What is soft-start, soft-stop?

The greatest benefit of having a garage door which features soft-start and soft-stop technology is that it is very quiet, a great benefit for those of you who have a bedroom or family room situated above your garage. With a soft-start/soft-stop opener, the door is accelerated until it reaches a predetermined rate of constant speed. Just before closing, the door is decelerated. The technology was devised as a means of lengthening the life of garage door openers.  Stress is reduced on the drive train making the technology particularly beneficial on larger, heavier doors.