A Cape Seal is a two-step pavement preservation process that combines two surface treatments. Cape seals are a chip seal covered with a slurry seal. A chip seal is a liquid asphalt layer that is covered with ¼ to ½ crushed rock. This is then covered with a slurry seal (asphalt emulsion mixed with sand) and provides protection to older asphalt pavement surfaces.

The City’s 5-year street maintenance program identifies streets, through an objective software program algorithm and consultant review, that achieve the most effective use of limited City funding to keep the City’s overall pavement condition at the highest level possible. The City uses the Metropolitan Transportation Commission’s (MTC) pavement management program, StreetSaver, to develop the City’s 5-year street maintenance program. MTC requires Bay Area cities to have a pavement management program in place to manage their street network in order to be eligible for pavement grant funding. MTC developed the program in the late 1980’s after determining cities were not effectively using their pavement money to keep the overall pavement conditions as high as possible. This was because many cities used a costly “worst-first” approach to pavement management. This approach put the majority of pavement funding towards the worst pavements allowing many pavements in better condition to drop down into more expensive repair categories, instead of maintaining these streets with less expensive treatments earlier on to keep them in good condition. Pavement management systems are built on the premise of keeping good streets in good condition and preventing streets from dropping into more expensive repair categories, which allows a larger number of streets to be treated at a lower price. The October 12, 2020 pavement management Council report addresses a stopgap strategy to treat streets in the poorer condition categories.

MTC’s pavement grant funding is tied to the use of the StreetSaver software program because the program is objective and mathematical, using a scientifically developed algorithm that inputs the available pavement maintenance budget, existing pavement conditions and street classification (residential, collector, arterial) to develop the program. Once the program selects a list of streets, the City’s pavement consultant provides an engineering review on each street to verify the appropriate treatment is used. Additional elements of the review include review of streets dropping into more expensive repair categories, grouping streets for better contractor bid pricing and removal of streets with upcoming development and utility construction projects. The developed 5-year street maintenance program is the most cost effective way to use the available pavement maintenance funds to keep the City’s overall pavement condition at the highest level possible.

There are more streets that need repair in the City than there is available budget. With limited funding, the program is only able to select a limited number of streets. As more funding becomes available, the program would select a higher number of streets for treatment.

A “Stop Gap” treatment is a road maintenance treatment put on streets in the poor condition category to prevent these roads from falling into expensive reconstructions. The City’s 5-year Street Maintenance Program uses cape seals as a Stop Gap treatment on City streets to keep these poorer condition streets from further deterioration.

No, please use the Citizen Portal link to send us the location of the pothole. On the next scheduled pothole repair day, the Public Works street crew will fill the pothole with hot asphalt. This is not a permanent repair but can help minimize the potholes until such time that the road is rehabilitated.

A slurry seal is composed of asphaltic emulsion (oil and water) and aggregates applied on top of the existing pavement surface at an average thickness of 1/8 to 1/4 inch. The slurry mixture seals the pavement from water intrusion, which is the leading cause of deterioration of a street. By regularly sealing the street, the City can extend the life of the streets in better condition, to prevent these streets from dropping into more expensive repair categories. The most cost-effective pavement maintenance programs use slurry seals to keep good pavements in good condition.

Once applied, the slurry seal composition takes about four to six hours to cure in warm weather.

On-street parking will be available within adjacent streets outside of the project limits. Pay close attention to parking notices and park off affected streets during construction. All cars in the “No Parking” zone during construction time will be towed.

Once the street is coated, it will be closed for approximately 4 to 6 hours. The street should be reopened by the end of the working day.

Yes. The contractor will coordinate with and accommodate trash, recycling and green waste pick-up.

Yes, the contractor will work with USPS or other delivery services.

Construction will not occur during the weekends or holidays.

Avoid producing water runoff into the streets the day before or after construction, because this may delay work. Also, keep children and pets away from construction areas.

Construction phases may take place at different times, extending work on your street across several days. We appreciate your cooperation and support and encourage you to call the Engineering Division at (650) 738-3767 if you have questions or concerns.

Due to the nature of a slurry seal treatment, there is an anticipated loss of asphalt material. On average, 10 percent of pavement material is lost over the first 30 days. This fluctuates depending on traffic. The contractor will be scheduling periodic street sweepings on the affected roadways during the first 30 days after the treatment has been applied to reduce loose sand.

Cape seals require a chip seal before placement of the slurry seal. The chip seal is small rock imbedded in a sticky liquid asphalt coating. Before placement of the final slurry seal (which is part of the cape seal), some of these small rocks may become loose. The contractor will schedule street sweeping to address this loose rock on the road. Once the slurry seal is placed, the rock will be covered and will no longer become loose.

A slurry seal and cape seal are different from an asphalt overlay. They provide a cost-effective method to seal the surface of the pavement, protecting the pavement and adding years of life to the pavement. However, because they simply coat the surface and do not add significant thickness, existing asphalt surfaces will not feel smoother following these treatments.