One hundred percent of tree material removed during the preconstruction activity was recycled or salvaged by Green Waste Recycle Yard in Richmond, California.
More than 50 native plant species, for a total of 45,000 plants, were collected in the Presidio prior to constriction and are now being grown in the Presidio Nursery.
Many of the piles for the high viaduct will be 12 feet in diameter, requiring a special oscillator rig for installation of the piles. Larger, deeper piles mean fewer piles are necessary, opening views from the Presidio to the bay.
The new parkway will allow pedestrians and bicyclists to cross over or under Doyle Drive in accordance with the Presidio Trails and Bikeways Master Plan.
The new parkway will have larger 11- and 12-foot lanes to accommodate buses and provide an improved experience for drivers.
Each weekday, nearly 120,000 vehicles travel between Marin and San Francisco over the Golden Gate Bridge along Doyle Drive.
The start of construction of the Presidio Parkway was accelerated by more than a year thanks to the receipt of $50 million in federal stimulus funding.
The new parkway will improve traffic safety by including continuous shoulders for emergency and disabled vehicles.
The first set of tunnels, the Battery Tunnels, will be constructed north of the San Francisco National Cemetery and span 853 feet.
Halleck Street will be closed and temporarily removed during construction. Upon completion of the Main Post Tunnels, Halleck Street will be restored over the top of the new tunnels.
The Main Post Tunnels will be constructed north of the Main Post parade grounds. These will be the longer of the two sets of tunnels, spanning 1,017 feet.
$3.6 million went directly to small and local businesses for the project’s first preconstruction contract (tree removal and native plant and seed collection).
The new parkway will include extended bus bays on both sides of Richardson Avenue.
Seismic safety will be achieved in 2011 when traffic is transferred onto new structures and the temporary bypass adjacent to the existing facility.
A robust Disadvantaged and Small Business Enterprise Participation Program has been established to actively engage businesses throughout San Francisco, the Bay Area, and California to participate in the project.
The northbound and southbound roadways will be separated by a wide, landscaped median improving driver safety and creating a parkway feel.
Both sets of tunnels will be constructed using the cut and cover method by digging into the natural bluffs and covering the tunnels with a green pedestrian corridor.
Including a temporary bypass in the construction phasing reduced the construction duration by nearly two years.

Safer Roadway

Replacing the old, corroded Doyle Drive with a new, structurally upgraded roadway will provide tremendous seismic and traffic safety improvements, particularly in the event of an earthquake.

Replacing Doyle Drive with an earthquake-safe facility is a high priority, as portions of the roadway currently rate only 2 out of 100 in structural sufficiency. Also, the original Doyle Drive design does not meet current roadway safety standards. The likelihood of serious accidents increases as a result of nonstandard design elements, such as narrow lane widths, lack of barriers separating opposing traffic, and lack of shoulders for use by disabled or emergency vehicles. The Presidio Parkway design improves stopping sight distances, deceleration lengths, ramp geometry and more. The typical lane width of the roadway will be increased to 11 feet, with an outside lane width of 12 feet to accommodate buses. Usable outside shoulders will be added to improve emergency response and provide a refuge for disabled vehicles.

The new Doyle Drive will also enhance pedestrian and bicyclist safety, providing well-defined pedestrian routes, incorporating pedestrian safety zones and including well-delineated bicycle lanes.