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.
Seismic safety was achieved in early 2012 when traffic was transferred onto the completed permanent southbound structures and a temporary bypass.
The final roadway, which opened on July 12, 2015, has improved traffic safety with wider lanes and continuous shoulders to improve emergency response and provide a refuge for disabled vehicles. The final Presidio Parkway design improves stopping sight distances, deceleration lengths, ramp geometry and more. The typical lane width of the roadway was increased to 11 feet, with an outside lane width of 12 feet to accommodate buses.
The new Doyle Drive also enhances 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.