City of Naperville's Vehicle Replacement Scoring Model
Jim Inglese, Fleet Services Manager, and Nels Olson, Fleet Analyst, City of Naperville, Illinois
One of the toughest issues concerning municipal fleet managers is determining the ideal time to replace vehicles and equipment. Dispose of it too soon and you waste productive fleet life and capital funds. Wait too long and you will be burdened with an unreliable unit that can strain your maintenance budget.
The Fleet Services Division of the City of Naperville, Illinois has developed a unique and successful Vehicle Replacement Scoring Model. Located 35 miles southwest of Chicago, Naperville is an award-winning city with a population of 140,000. According to Jim Inglese, Fleet Services Manager for the 570-vehicle Naperville fleet for the last 14 years, "Our current model has evolved from a combination of different vehicle replacement models, our experience and knowledge of the relevant variables, and accurate vehicle repair coding and cost histories. As our model evolved, we have 'back tested' scoring model changes against past replacement decisions for validation."
The City's replacement program is funded by a dedicated Vehicle Replacement Fund which is replenished from intra-departmental monthly charges. All vehicles and equipment are assigned a fixed service-life-cycle, expressed in months, based on the vehicle or equipment classification and replacement history. The charge is calculated by dividing the vehicle replacement cost by the assigned service-life of each unit in months. If units are retained past their designated service-life, the replacement charge is reduced to 10% of this amount.
When a vehicle is within the last two years of its scheduled life cycle, it becomes a candidate for annual Replacement Scoring. If its Replacement Score exceeds the replacement criteria score, it is scheduled for replacement in the next fiscal budget year. If it scores below the criteria, it is retained and scored again each year until it exceeds the replacement criteria score, even if it exceeds its assigned replacement age.
The scoring is totaled using scores on the following six performance and cost variables:
Replacement qualification scores are 23 points for all sedans and light trucks and 28 points for heavy-duty vehicles and off-road equipment whose gross vehicle weight rating (GVWR) exceeds 10,500 lbs.
"This scoring model has been very successful for Fleet Services and the City," states Inglese. "The ability to quantify replacement decisions is supported by Finance, City Manager, and elected officials. The model has also justified extending the economic life of many units resulting in the savings of tens of thousands of dollars in annual capital spending. From a maintenance and reliability perspective, we have flattened expenditure increases and extended the in-service time for our customers."