Optimal Replacement Cycles of Highway Operations Equipment (2018)

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57 C H A P T E R 4 For the optimization tool to be universally applicable, it is necessary to adopt a standardized equipment classification numbering scheme. Table 4 shows the 40 major equipment classes that are preloaded in the optimization tool, each of which has class-specific default replacement factors built into the tool. The numbering scheme follows closely the equip- ment classification codes adopted by the National Associa- tion of Fleet Administrators (NAFA). Most of these class code descriptions are self-explanatory; however, two may need further clarification: • Class 8786, Bottom Dump, is used to describe the full bottom dump truck unit, including the tractor and bot- tom dump trailer. Although few agencies have these units in their fleet, this class is included as one of the major equipment classes. • Class 0110, Salt Spreader, uses the same number as the general NAFA class for “Snow Removal” units. For the purposes of analyzing life cycle cost in the optimization tool, this class code represents a generic type class description for salt spreaders, regardless of the configuration or type of salt spreader used by the agency. This class code may be used for tailgate spreaders, drop-in spreaders, or any other configuration that is most prevalent within the agency. Because these units typically do not have hour meters, their utilization is measured by hours of usage reported by maintenance crew daily reports. These class codes are used by the optimization tool and are not intended to replace an agency’s class codes. The agency’s internal equipment classification and num- bering scheme are likely unique, developed specifically to fit the agency’s needs. Some agencies have very detailed schemes with many class codes, while other agencies have more gen- eralized class schemes. The optimization tool adopts a more generalized scheme. A cross-reference table between the tool class codes and the agency’s class codes will be needed. Table 5 provides an example of cross-referencing for the ½-ton pickup class. In this example, five different pickup types are included in the universal ½-ton pickup class under Code 1521. In this way, the optimization tool analyzes all of the agency classes using the replacement factors for tool Code 1521. When performing LCCA for the ½-ton pickup class, the user has the option of analyzing all five classes under Code 1521, or any one, or a combination of the five classes. Likewise, the user may analyze subgroups within a class such as equip- ment manufacturer (e.g., GMC versus Ford). However, there should be enough units in the class to provide a valid sample for performing a class-level LCCA. It should be noted that categorizing equipment class codes at a level too low could affect the quality of results when performing class-level LCCA. Having too few equip- ment units in a class may lend an unrealistic class average cost analysis. When performing replacement analysis in the optimiza- tion tool, the agency’s class codes that correspond to equip- ment class codes preloaded in the tool can be used as inputs. Equipment Classification Structure

Tool Code 1300 1600 1348 1521 1531 1523 1533 1424 3514 2513 3711 3744 6712 8712 8785 8786 8810 8743 8744 8771 8741 8773 8778 8731 9452 9132 9220 9110 9160 9440 9441 9150 9250 9230 9290 9142 9431 9426 9623 0110 Maintenance Equipment Equipment Class Passenger Vehicles Light Trucks Medium Duty Trucks Equipment Group Large Trucks Specialty Trucks Heavy/Off-Road Equipment Description Sedan SUV Police Cruiser ½-Ton Pickup ¾-Ton Pickup ½-Ton Crew Cab ¾-Ton Crew Cab Vans Mechanic Shop Truck 1-Ton Crew Cab Flat Bed Truck Scissor-Bed Truck Single-Axle Dump Tandem Dump Tri-axle Dump Bottom Dump Tractor/Trailer Bucket Truck Bridge Snooper Truck Roadway Sweeper Truck Mobile Crane Culvert Cleaner/Vacuum Truck Asphalt Distributor Wrecker Truck Striping/Paint Truck End Loader, Wheeled End Loader, Track Loader, Skid Steer Motor Grader Roller, Pneumatic Roller, Steel Wheel Excavator, Wheeled Excavator, Track Dozer Dragline Backhoe Asphalt Paver Pavement Profiler Tractor, Mower Salt Spreader Table 4. Equipment groups, tool codes, and equipment classes. Tool Class Agency Class Code Description Code Description 1521 ½-Ton Pickup P2131 2WD Regular Cab, Gas P2132 2WD Regular Cab, Diesel P4131 4WD Regular Cab, Gas P4132 4WD Regular Cab, Diesel P4252 4WD Extended Cab, Diesel Table 5. Example of class cross-referencing for ½-ton pickups.