Item B: Funding Strategies for Transportation System Operations, Maintenance, and Preservation

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would average all streets together and review their performance over time. He said there were default models in the software, a critical component, to arrive at a better performance. Mr. Furber explained that the default model came into play approximately 60 percent of the time. He remarked that (1) 37 percent was a weighted average of all the classifications; (2) an increase in the life of major arterials, which accounted for approximately two percent of the total system lane-miles, could be as high as 85 percent; and (3) an increase in the life of residential streets, which accounted for approximately 70 percent of the system, was approximately 30 percent. In response to a question from Mr. Mulligan, Mr. Furber confirmed that the slurry seal was the most effective method to maintain the condition of residential streets and more economical than doing overlays. He elaborated that the primary failure on residential streets was the aging of asphalt concrete and that applying slurry seal within 3 to 5 years would prevent the age-related cracking. Mr. Furber estimated that at least 8 to 10 years of life (possibly up to 20 years, based on the City of Vancouver’s experience) would be possible for residential streets with the application of aggregate slurry seal, and that this application could be applied at least two to three times. He added that residential streets with bus routes were a different situation, because the buses will more quickly cause structural failure to the pavement. In response to a question from Mr. Wanichek, Mr. Furber responded that, in simulating the $8.5 million annual funding applied to the preservation backlog, the unit cost used included the Citys engineering and = administration costs, testing, ancillary/associated work, and the effects of inflation. He noted that 22 percent was the average percentage, based on actual City experience, used for estimating those City costs as a percent of the construction cost. He said in some cases, the actual cost items were quite high as a MINUTES- Citizen Subcommittee of the Budget Committee September 19, 2001Page 4