San Francisco's soon-to-be-tallest building has undergone design changes for its Planning Commission review next month. The latest revisions of the Transbay Tower's design add a sculptural element to the top and connect the street to the 5.4-acre park planned for the roof of the transit center with a diagonal elevator.

In the new design, the building's "crown" stretches the tower 150 feet above the highest occupied floor.

"We wanted something visible at urban scale but almost Zen-like in its simplicity... the idea is to further lengthen and slim the profile and also create something more distinctly emblematic of the city," architect Fred Clarke told local media.

The latest revision also includes a small plaza that will connect the tower to the urban park 80-feet above street level on the roof of the Transbay Transit Center. An inclined track will move people from the sidewalk to the park through a grove of redwood trees. One corner of the tower's base will also be opened to create a public lobby with seating, shops and an express elevator to the rooftop park.

Mayor Edwin Lee has already signed off on the plan for the Transit Center District. The tower only needs final approval from the Planning Commission before developers can start construction in 2013. The hearing is scheduled for October 18th.