Demonstrating an Empirical Tool to Predict Fleet-Wide Heavy-Duty Vehicle Fuel-Saving Benefits from Low Rolling Resistance Tires

Abstract

The United States Environmental Protection Agency has identified the use of low rolling resistance (LRR) tires as an effective fuel-saving technology for heavy-duty vehicles (HDV). However, adoption of LRR tires has been less than desired because of potential performance uncertainties under real-world operating conditions. Also, previous decision-support tools developed to help stakeholders have had limited accuracy because of inherent transient speed profiles in real-world operating cycles. This study develops a tool to predict HDV fleet-wide fuel saving from LRR tires. The tool uses empirical models to estimate the fuel-saving benefits of LRR tires as a function of vehicle characteristics, operating cycles, and route characteristics. To facilitate ease-of-use by stakeholders, the empirical models have been transformed into a Microsoft Excel spreadsheet tool. The empirical models were developed with data generated by simulating real-world HDV operating cycles with Autonomie, an advanced model for automotive control-system design, and simulating vehicle energy consumption and performance. Validation analysis of the tool shows an average error of less than 6.5%. Unlike previous tools, the developed tool is applicable to both stabilized and transient speed operations. It allows users to customize it to their specific fleet and operating conditions. This is significant and it is envisaged that the tool will facilitate more investment decisions by fleet operators, as well as help regulatory agencies and policy analysts design key policy incentives.