Guide for Utilization Measurement and Management of Fleet Equipment NCHRP 13-05

Transcription

1 Guide for Utilization Measurement and Management of Fleet Equipment NCHRP Ali Hajbabaie, Ph.D. Department of Civil and Environmental Engineering

2 Objectives Develop a guide for utilization measurement and management of fleet equipment to be used by State highway agencies Prediction Models Develop statistical models to predict utilization for each equipment asset Formulate utilization cost functions and constraints to satisfy demand for each asset Validate models Management Framework Develop optimization models to: - Minimize total costs - Determine optimal utilization values - Determine optimal fleet size - Determine optimal relocations 2

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4 Initial Questions to be Answered What are utilization measurement metrics? Which factors influence equipment utilization? Which equipment to consider? What kind of data to collect? How much? How many years? 4

5 Literature review and Survey Published technical reports (NCHRP, state DOTs, etc.) Journal and conference (TRR, TRB, etc.) White papers Unpublished work Survey to all state DOTs 32 responded 5

6 Candidate Asset Utilization Metrics Annual mileage Annual engine hours Usage over the last 12 months Frequency of use 6

7 Candidate Factors Influencing Asset Utilization 33 factors were mentioned Downtime duration Asset age Cumulative utilization Normal equipment life Unskilled/skilled operators/mechanics Agency management policies/practices Expected workload Supervision level needed Design complexity Environmental impacts Cost 7

8 Equipment Types Dump Truck Pickup Truck Automobile Van Sport Utility Trailer Front Loader Grader Mechanical Street Sweeper Truck Air Street Sweeper Truck Sweepers / Scrubbers Riding Mower Truck Tractor Snow Removal Attachment Roller Drill Asphalt Distributor Attachments Man Lift Large Truck with Special Body 8

9 Data Availability and Willingness to Share Does the provided equipment list represent equipment classes that your agency use? 89.5% Yes, 10.5% No Data availability More than 50% said not available Rent reason, Annual rent hours, Rent costs, Annual idle hours, Annual interest charge, Annual taxes, Annual licensing fee, Annual storage cost, Predicted annual demand Less than 30% said available Asset capacity, Annual downtime hours, Seasonality, The frequency of usage Willingness to share: 19 states 9

10 Data Collection Sent the request to 19+ DOTs, received data from 8 California Florida Idaho Minnesota Montana North Carolina Utah Washington 10

11 Data Processing Data aggregated at the county level Outliers were removed Three data sets could be used We had enough data for eight equipment types Data allowed fitting models for annual mileage only 11

12 Fitting Predictive Utilization Measurement Models Model structures considered: linear, quadratic, power, logarithmic, and nonlinear Logarithmic regression yielded the best fit and the most intuitive prediction models The backward elimination approach used to fit the models Pearson correlation test for multicollinearity between independent variables Performed other tests to ensure all assumptions of regression analysis are met 12

13 Example: Dump Truck Utilization Prediction Model YY: Log (Annual Mileage) Estimate P-value Intercept Annual Fuel Cost Log (Annual Downtime Hours) In Service Age Class Class Low Usage Adjusted R-Square 0.98 Sample size 164 YY = xx FFFF log xx DH xx ISA xx C xx CC xx LU 13

14 Example: Dump Truck Utilization Prediction Model 40 Count Residuals : predicted mileage observed mileage 14

15 Example: Dump Truck Utilization Prediction Model Predicted Annual Milea y x 10 R Observed Annual Mileage 15

16 Equipment Type Utilization Prediction Model Dump Truck xx FFFF log xx DH xx ISA xx C xx CC xx LU 0.98 RR 22 Pickup Truck xx PPPP xx FFFF log(xx DDDD ) xx FFFF xx CC xx CC xx CC xx LLLL 0.98 Automobile xx SSSSSS log(xx FFFF ) xx IIIIII xx FFFF xx LLLL 0.98 Van Sport Utility Vehicle Grader Mechanical st. sweeper Large trucks xx PPPP log xx FFFF log xx DDDD xx IIIIII log xx FFFF xx CC xx LLLL xx SSSSSS xx UUUUUU log xx FFFF log xx DDDD log xx FFFF xx LLLL xx SSSSSS log(xx FFFF ) xx IIIIII log (xx FFFF ) xx LLLL xx PPPP (xx SSSSSS + xx UUUUUU ) log(xx FFFF ) log(xx IIIIII ) xx FFFF xx CC xx PPPP xx SSSSSS xx UUUUUU xx FFFF xx DDDD xx IIIIII xx FFFF xx CC xx CC xx 0.98 LLLL

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18 Utilization Management Objective: minimize total cost (fixed and operational) Control Decisions County/region/division level in a year fleet size of a specific asset number of assets to be purchased number of assets to be salvaged number of assets to be relocated within a state average utilization level 18

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24 Relocation Example 24

25 Guide for Utilization Measurement and Management of Fleet Equipment NCHRP Ali Hajbabaie, Ph.D. Department of Civil and Environmental Engineering

26 Research Team Ali Hajbabaie Leila Hajibabai Wei (David) Fan Mehrdad Tajalli Amir Mirheli WSU SBU UNCC WSU SBU Xianming Shi Mike Moser Shaowei Wang Miao Yu WSU MyFleetDept ITSNode UNCC 26