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in the left side axis. The impacts to the pavement condition can be seen in terms of early <br />degradation (more rapid decline in predicted PCI). For example, the PCI is predicted to reach a <br />value of 40 at about 6'/2 years from the beginning of the analysis period rather than about 8 years <br />without the additional heavy vehicles. The analysis tool does not incorporate the possibility that <br />the local agency might apply a chip seal or overlay to the pavement. The relative impact to the <br />pavement structure will be the same regardless. <br />Similarly, the overall accumulation of predicted ESAL applications can be seen in the figure as a <br />result of the expected traffic and the unexpected additional heavy vehicles. <br />100 <br />90 <br />80 <br />70 <br />a 60 <br />m 50 <br />40 <br />a 30 <br />20 <br />10 <br />PCI Without Additional Heavy Vehicles <br />PCI With Additional Heavy Vehicles <br />ESALs without Additional Heavy Vehicles <br />ESALs With Additional Heavy Vehicles <br />01 <br />I <br />K <br />` <br />10 15 20 <br />Years since Beginning of Analysis <br />Figure 3. Sample results from segment analysis. <br />Network Analysis <br />1,200,000 <br />1,000,000 <br />N <br />800,000 <br />W <br />600,000 2 <br />a <br />400,000 E <br />U <br />200,000 <br />The network analysis provides an overview of the entire network with the application of the <br />heavy vehicles specified by the user. The same set of heavy vehicles is applied to all roads in the <br />network. Due to the summary nature of the analysis, detailed information on specific roads <br />cannot be provided in the results pages. The network report provides total impact cost <br />information, assuming that all vehicles are applied to all streets. As described in the previous <br />chapter, the total cost of consumed life, over the entire network is reported, as well as the total <br />cost of additional asphalt to upgrade the network to accommodate the additional heavy vehicles. <br />The two methods of computing the cost of impacts will not provide exactly the same results, <br />since they are computing completely different impacts. They are almost always close to each <br />other however. For example, in the example in Figures 20 and 21 shows that the percent life <br />consumed method predicted about $994,000 in impact costs, and the additional asphalt thickness <br />design method predicted about $1,227,000 in costs. Considering that these two methods arrived <br />at these values in completely different ways, it is a very close comparison. <br />23 <br />