City Smooths Streets with Recycled Tire Product, Gets Cost Savings & Paves More Blocks

9th Avenue on either side of Balboa with new Flex Seal treatment

Darker color with Flex Seal but some residents describe surface as bumpier

The San Francisco Department of Public Works (DPW) is experimenting with a new street paving treatment that re-uses old tires and leaves surfaces smooth and, reportedly, safer. Flex Seal, according to its manufacturer, is a "revolutionary asphalt emulsion" that mixes the recycled tires with asphalt, polymers, and other agents. The new product is less expensive and helps stretch DPW's under-financed street repair budget to repave many more blocks. In San Francisco Flex Seal has been tested primarily on dozens of local, neighborhood blocks that receive less wear and tear. These blocks appear much darker than others with regular asphalt applications, and the surfaces are expected to retain their color longer. The Flex Seal blocks have a more textured feel than just-applied asphalt, and a few residents think the surface is bumpier than with asphalt.

The lower costs of the treatment are persuasive, but Flex Seal paving has won high marks from public works departments in other California cities for the product's effectiveness as well. In Los Angeles and San Clemente, street repair directors have found that the product yields significant protection from sun and water damage. The rubberized material inhibits oxidation of oils that give pavement surfaces their flexibility and deters the development of cracks. Keeping water from entering into cracks and seeping into the street sub-base is essential to preserving the integrity of the surface and preventing further damage. The pavement protection has a five-year life cycle, according to the manufacturer's marketing promotion. Although San Francisco is currently testing the treatment only on less-used streets, two other types of Flex Seal have been developed for use on busier collector streets and on high-volume traffic corridors.

The verdict is out on Flex Seal for use in San Francisco, but the treatment does seem to yield additional benefits:

• traffic on road surfaces with the new seal are reportedly less noisy
• the dark surface yields a greater contrast with lane striping, possibly resulting in greater safety
• surfaces seem to give tires a better grip, even when wet
• 100 discarded tires are re-used for each mile of product application, putting a slight dent in the 273 million tires that get tossed every year

The San Francisco Bicycle Coalition is encouraging its members to take test rides on streets with the new treatment to determine rideability and degree of tire grip when the surfaces are wet. Check the SFBC Good Roads page for a list of streets. We will report further on the surfaces and provide a more extensive list of city blocks with the Flex Seal treatment in the days ahead.

Steiner Street on the Wiggle NOW Safer

Seth Fischer is all for a smoother, safer Steiner Street on his commute

Surprise for cyclists turning northbound on Steiner from Duboce

One smooth 1/2 block; the southbound lane still needs work

This is why SFBC Good Roads Campaign blew the whistle on unsafe surface

Seth Fischer knows a smooth surface and that's what he got Thursday morning for his regular Wiggle spin from Duboce and northbound on Steiner. This stretch between Duboce and Herman has been one eyesore and hazard for some time. The Department of Public Works (DPW) has filled hole upon hole here in the past, but after the rains and especially the SFPUC/Water Department's construction on the south side of the street, only one option remained. Grind it out and add new smooth asphalt.

Neal Patel, Community Planner for the SF Bicycle Coalition, might have been the first to fully appreciate the change in the surface. Last night his ride on Steiner brought one huge smile from the just-completed paving. Just last week he was on the block with DPW reps urging quick action for the street defects. "As soon as the rain stopped enough for them to get out there, work crews took care of the problem," Patel said, "and they did a great job."

So, cyclists, enjoy the northbound lane, and here's the story on the bumpy utility trench work on Steiner southbound from Waller to Duboce. SFBC is also pushing for this work to be either re-applied or smoothed out by some other means as soon as possible. DPW managers are working with SFPUC to address the problem. Normally if utility work involves a cut that is 25% or longer of the given block, the full length of the block from curb to mid-point needs to be repaved. In this case, the city allowed a waiver since these blocks are due to be re-paved curb-to-curb after August 1st of this year. Budgets are tight, and SFBC volunteers* report just the real hazards to the city, not the regular inconveniences of the road. Given the huge amount of bicycle traffic that the Wiggle gets everyday, a wait of seven months or more seemed unwise for either the cyclists or the city's liability status.

This morning I also walked the block of Sanchez south of Duboce. Cyclists know how bad this block has been as well. A neighbor and homeowner from that block stopped by to chat -- and complain about the terrible street surface SFPUC left in its wake once they believed construction was done. After he heard about SFBC's efforts to get these streets smoothed, he smiled and said, "It's great to work on these problems as a community together; I really appreciate that the bike coalition is working on this." He also said he was going to get his neighbors to call 311 requesting a better pavement job.

*Full disclosure: Along with several other volunteers, I am a member of the SFBC Good Roads Crew.

Use 311 for NOPA Potholes

Even on NOPA's relatively smooth streets, potholes keep appearing. It's not that these holes, dips, and rough spots never get fixed. Wear and tear -- especially on Muni lines -- take their toll. And NOPA's lurking, dropping sinkholes suck in the temporary asphalt repairs.

The worst streets in NOPA for potholes and other street defects? Divisadero certainly, and its makeover can't begin soon enough. Masonic has its share of hazards, and lower Central, from Fulton to Hayes, is all about recurring sinkholes. For bicyclists, the McAllister ride through NOPA is rough and bumpy even without gaping craters. (For a full review of pavement conditions in NOPA, see previous posts here and here).

The best way to get rid of potholes is to report them to 311, by phone or online. The Dept. of Public Works has a good record of getting the problems fixed within a few days, sometimes longer. The San Francisco Bicycle Coalition's Good Roads program has been monitoring city streets intensively for potholes since April of 2008. During that period, SFBCers have reported more than 1500 potholes to the city through 311. About 50 of those street defects were located on NOPA streets. And yet they keep showing up, such as this one circled in spray paint yesterday on Broderick at Grove. (Note: DPW provides the paint; we're not renegade street taggers. The paint helps DPW locate the hole and it also alerts cyclists of areas to avoid until the fix occurs).

NOPA cyclists: Join the SFBC Good Roads Crew the first Saturday of every month as we target a different neighborhood to identify, circle, and report every pothole, crack, ridge, and sunken utility cover we can find. A group of 6-12 of us meet up at 10 am and conclude by noon and then gather at a neighborhood spot for cold drinks and lunch. We're a very friendly group, and newcomers are always welcome. Check the SFBC Chain of Events and the Good Roads page for meeting spots. (note: no ride this holiday weekend; next ride October 3rd).