Subject: STREET SEALING ALTERNATIVES
COUNCIL DISTRICT: City-Wide
Approve the use of slurry seal as the preventive maintenance seal treatment for the City’s residential streets for the 2002-03 maintenance season.
The City Council identified the review of residential street maintenance treatments as one of the top priorities in its Fall 2001 policy priority setting session. Staff prepared a report to respond to the policy issues raised in that session within the context of the 10-Year Street Maintenance Recovery Plan. The Finance and Infrastructure Committee reviewed the report on February 27th and referred the issue to the City Council. The original report thoroughly detailed the advantages and disadvantages of various street sealing treatments. On March 19th, the full City Council reviewed the report and requested additional information.
A subsequent report was presented to and reviewed by the City Council on April 30th. The report included information on sealing alternatives, further cost comparisons with other jurisdictions, treatment impacts within the “Cool Communities” context, and the identification of streets currently in need of more extensive maintenance treatments. The City Council directed staff to return with a final recommendation as to what seal treatment should be used on San Jose’s residential streets.
Chip seal has proven to be a cost-effective residential street maintenance treatment over the years, helping the City maintain a large network of neighborhood streets in relatively good condition. The primary benefits of the treatment are its durability and life-cycle cost. The implementation of the 10-Year Street Maintenance Recovery Plan has enabled the City to maintain more miles over the past six years than at any point in its history. The majority of the miles maintained received a chip seal treatment, focusing added attention on the chip seal treatment process that had not been the case with more limited programs in years past.
Research on other jurisdictions, including survey information in previous staff reports, has always revealed that most Bay Area and California cities use or have switched to slurry seal from chip seal because of its visual aesthetics, smoother surfaces, and resident satisfaction. In addition, staff’s review of the survey work that Councilmember Dando’s Office conducted on other jurisdictions confirmed that slurry seal is the predominant sealing method on residential streets, primarily for the reasons mentioned above. Finally, staff indicated in our previous report that a light colored aggregate can be used in slurry seal improving its compatibility with the “cool communities” initiative.
Even though 71% of respondents to our chip seal survey thought it to be a good service overall, chip seal has received the largest number of complaints of any of the City’s street maintenance treatments. The complaints received from residents and identified in previous reports to the Council include: loose rock and gravel, rough surfaces, and less aesthetic looks in residential neighborhoods. These complaints are caused by the inherent nature of the chip seal product.
The level of concern that chip seal treatments have generated with residents, and the fact that it resulted in a City Council policy referral, led staff to develop further refinements to the chip seal treatment process that were intended to be used in the 2002 maintenance program. The refinements were developed in the event the City Council decided to continue the use of chip seal on residential streets. The refinements included specifying a uniform size rock to improve retention and reduce loose rock, additional street sweeping, informational posting and towing provisions to more quickly and thoroughly remove loose rock, and the inclusion of crack sealing as part of the application process. The refinements were considered necessary if the concerns of residents were to be mitigated and the acceptability the chip seal treatment was to be improved.
Normal preparations for the 2002 maintenance program included the receipt of preliminary bid prices for the refined products and services that were being considered for the chip seal treatment process. The refined products and services have resulted in an estimated unit cost of $1.28 per square yard, up from the $1.07 that standard chip seal applications have cost the City in years past. The estimated unit cost of the chip seal treatment per square yard was compared to the estimated cost of slurry seal (for residential streets only), which, as mentioned in the April 30th report can be as low as a $1.22 a square yard. The comparison indicates that the estimates for the two treatments are very close in cost.
The inherent advantage of chip seal is its durability and cost over its useful life. The product characteristics enable chip seal to be used for up to 10 years between treatments as compared to 8 years for slurry seal. A residential slurry seal program requires additional miles of streets to be treated each year, to enable the 8 year cycle to cover all residential streets in the City and keep streets in a prescribed condition. The impact of the change to slurry seal would, however, not be felt until the end of the 10-Year Recovery Plan because the chip seal treatments, applied during the first half of the recovery effort, are expected to last 10 years delaying the need for increased slurry seal miles until 2006-07. The estimated cost impact of maintaining the additional miles, in current dollars, is approximately $500,000 starting in 2006-07.
The delay in the need to increase annual sealing requirements until 2006-07 provides the time to secure the needed funds to maintain the additional miles that a slurry treatment requires. In 2004-05, additional federal funds of $6 million for street maintenance are anticipated to become available. In addition, $10 million will become available from Proposition 42 funds, approved by voters in March 2002, in 2008-09. In the intervening years, staff will be seeking other funding sources as well to meet the needs of the overall street maintenance program.
The City is at a decision point that many other jurisdictions have encountered. While proving to be a durable treatment, chip seal also has negative impacts that are proving to be unfavorable to residents and not only difficult, but increasingly costly to mitigate. At this time, staff recommends that the City Council approve the switch to slurry seal as the primary preventative seal treatment for residential streets. This switch will not affect the amount of miles that will be treated in 2002-03 or in any of the remaining years of the 10-Year Recovery Plan and is expected to improve resident satisfaction with street maintenance.
If the switch to slurry seal is approved, staff will report any noteworthy developments resulting from the change during 2002-03. Furthermore, the Transportation City Service Area will work with the City Council through the 2003-04 budget process to develop a plan to address future street maintenance needs.
This report has been coordinated with Public Works and the City Attorney’s Office.
Wayne K. Tanda
Director, Department of Transportation