Replacing the old, corroded Doyle Drive with a new, structurally upgraded roadway provides tremendous seismic and traffic safety improvements, particularly in the event of an earthquake.
The historic Doyle Drive design did not meet current seismic or roadway safety standards. The likelihood of serious accidents was increased by the presence 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 temporary bypass that will carry traffic from April 2012 until project completion meets current seismic safety standards and greatly improves traffic safety through the use of a moveable median barrier.
The final 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.
Watch the Exploratorium’s "Science in the City" video discussing the High Viaduct’s seismic hinge.