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49 life of the system can be fairly short and pavement rehabilita- data being collected. They are also needed for calibration, tion may not be warranted, so long as the pavement condition routine scale calibration verification, site maintenance, and is adequate for collecting accurate weight data. In such cases, site repair in order to obtain the maximum value from the it may be unwarranted to construct a new 300-foot pavement funds spent on initial site implementation. slab for a WIM installation that is needed only to provide an Good data collection is not necessarily achieved by pur- accurate week-long sample during a particular commodity chasing the most expensive technology. What is necessary is movement (for example, during a harvest season) and where to correctly budget the resources needed to buy reliable equip- the existing pavement is reasonably smooth. ment, install that equipment properly, calibrate the equip- ment, and maintain and operate the equipment. The cost of performing these tasks will almost always be returned to the 5.4 BUDGET NECESSARY RESOURCES highway agency in improved reliability in the pavement design process. Initial site and equipment costs are not the only budgetary Similarly, the cost of poor data collection is most likely to requirements of truck volume and weight data collection. be made apparent in costs incurred as a result of poor pave- While a large portion of the data collection budget is associ- ment design. (That is, poor design resulting from bad input ated with initial system purchase and installation, these funds data is ultimately more expensive than collecting the data are poorly spent if the other tasks associated with data col- needed to create a good design.) lection are not also adequately funded. Staffing and other Table 5.1 (based on vendor- and state-supplied data) pro- resources are needed to collect, review, and summarize the vides general equipment costs. (Note that these costs will TABLE 5.1 WIM equipment estimated initial and recurring costs1 Deep Pit Site Cost Considerations Piezo Piezo Quartz Bending Plate Load Cell Initial Costs Pavement Rehabilitation2 ?? ?? ?? ?? Sensor Costs, Per Lane 3 $2,500 $17,000 $10,000 $39,000 Roadside Electronics 7,500 8,500 8,000 8,000 Roadside Cabinet 3,500 3,500 3,500 3,500 Installation Costs/Lane Labor and Materials 6,500 12,000 13,500 20,800 Traffic Control 0.5 days 1 day 2 days 3+ days Calibration 2,600 2,600 2,600 2,600 Annual Recurring Costs/Lane Site Maintenance 4,750 7,500 5,300 6,200 Recalibration 2,600 2,600 2,600 2,600 Notes: 1. These cost estimates have been developed based on a variety of published sources. However, costs vary over time and especially from vendor bid to vendor bid. Thus, actual costs can vary considerably from what is presented here. 2. Pavement rehabilitation costs are a function of current pavement condition, desired smoothness, desired site life, and desired WIM system accuracy. Consequently, they differ dramatically from site to site. At a given site, however, they will be similar for all technologies. 3. These costs can vary considerably based on the exact sensor configuration chosen for a given site, as well as the specific bid prices provided by vendors.