About the research
The objective of this research was to review current Iowa Department of Transportation (DOT) processes and procedures related to vehicle procurement, maintenance, operations, and sales and develop a tool to optimize equipment lifecycles. The study focused on single-axle A07 and double-axle A12 snowplows, as these represented 31.7% and 45.6%, respectively, of the fiscal year (FY) 2015 equipment replacement budget.
Using data currently collected by the Iowa DOT and the models developed, the researchers developed a decision support system (DSS) that recommends optimized normal replacement cycles for single-axle A07 and double-axle A12 vehicles. The objective of the DSS is to minimize equipment lifecycle cost while meeting the needs of Iowa DOT road service.
Based on the data provided by the Iowa DOT and the estimated resale value curve of the vehicles, this research indicated that the optimal replacement model is eight years for single-axle A07 vehicles and six years for double-axle A12 vehicles. Assuming the resale value curve is accurate, we estimate that the Iowa DOT would save approximately $1.8 million for single-axle A07s and $6.47 million for double-axle A12s per year by moving from a 15-year normal replacement model to eight years for single-axle A07s and six years for double-axle A12s.DO