San Francisco International Airport (SFO) closed Runway 28L on September 7, 2019, for 20 days to construct a new base layer below the runway surface. Once the runway closed on Saturday construction crews immediately began the process of removing the existing runway layers to create a new base layer below the surface. The runway is expected to reopen on Friday, September 27, 2019.
Traffic control in place for construction vehicles
During this 20-day period, SFO expects an increase in traffic volume at the intersection of Millbrae Avenue and Old Bayshore Highway, as construction trucks traverse this area to access the runway construction site to remove old pavement and deliver materials to create the new base layer and runway surface. At the peak of construction activities, up to 600 truck deliveries are expected in a 24-hour period.
Traffic control, via construction flaggers and/or SFO Airport Police, will be in place during this construction activity, and some lane closures may occur to facilitate this work. SFO staff have briefed the City of Millbrae on this anticipated activity. Drivers traveling through the area are advised to plan accordingly, by allowing extra time to travel in this area or take alternate routes.
Temporary change to nighttime noise abatement procedures
SFO’s Nighttime Preferential Runway Use program aims to maximize flights over water and minimize flights over land and populated areas during nighttime hours. During the 20-day closure of Runway 28L, the program, which normally operates between the hours of 10:00 pm – 7:00 am, will conclude an hour early, at 6:00 am. This move will allow for the increased usage of Runways 1L and 1R for departing flights, which will help mitigate the length of delays throughout the day, including the cascading delay effect that impacts surrounding communities in the late evening hours. Concluding this program an hour earlier than normal is expected to affect approximately 26 flights per day during the Runway 28L closure. The SFO Nighttime Preferential Runway Use Program will return to its normal 7:00 am end time when Runway 28L reopens, which is expected on Friday, September 27, 2019.
Anticipated delay impact, voluntary airline schedule reductions
Because the closure will reduce the Airport’s overall runway capacity, SFO advises travelers to expect delays during this period. Airlines have collaborated with SFO to voluntarily reduce their flight schedules to lessen the length of delays. When combined with reductions from other non-airline flight operations, total flights at SFO have been reduced by 13% during the 20-day period of the runway 28L closure. Airlines have also re-timed certain flights to reduce demand during peak time periods.
With the voluntary schedule adjustments in place, flight delays are expected to average 30-45 minutes, with some flights experiencing maximum delays of approximately 2 hours. SFO recommends that travelers opt for early morning flights before 9:00 a.m. PDT during this period, as delays are expected to begin after 9:00 a.m. PDT each day during the closure, and continue for the remainder of the day. Both domestic and international flights may be affected by this activity, with short-haul flights being most affected. The period of Wednesday through Friday will see the largest amount of flight activity, and thus the most potential for delays.
The closure is being conducted to construct a new base for Runway 28L, one of two runways used primarily for arriving flights, in the area where it intersects with Runway 1L and 1R, which are primarily used for departing flights. These runway intersections are the most heavily-traveled areas of the entire runway system at SFO, with more than 68% of all flights crossing these intersections.
The total length of Runway 28L is 11,381 feet. The project will reconstruct a 1,900-foot section of Runway 28L, replace lighting and drainage infrastructure, and overlay a 600-foot section of Runway 1L.
SFO repaved the entire top layer of Runway 28L in spring 2017. During this project, core sampling and ground-penetrating radar indicated that the base layer was showing signs of fatigue cracking due to the large amount of aircraft activity in this area. This issue required additional investigation and engineering that could not be addressed at that time. SFO staff have evaluated multiple options and concluded that the best long-term solution is to excavate the section of Runway 28L at the intersection of Runway 1L and 1R to reconstruct the pavement structure, comprised of a cementitious aggregate base and a top asphalt surface.
With input from airlines at SFO, the project team selected the period of September 7-27, 2019, for the closure to avoid the busy summer and year-end holiday travel seasons. This timeframe was also chosen for the low probability of precipitation, as dry weather is necessary for asphalt paving.
The contract for the Runway 28L Reconstruction project was awarded to Golden Gate Constructors. The project is federally-funded, and the total project cost expected to be $16.2 million.