Recommended Citation
Mwamba, I. C., Benny, D., John, A. P., Holguin Mejia, D. O., Song, D., Sabu, J., Dong, J., Pourgholamali, M., Modali, S., Ajagu, R. O., Agbelie, B. R., Volovski, M., Gkritza, K., Sinha, K. C., & Labi, S. (2024). Updating cost allocation and revenue attribution (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2024/23). West Lafayette, IN: Purdue University. https://doi.org/10.5703/1288284317764
DOI
10.5703/1288284317764
Abstract
This report presents a synopsis of the results from the 2024 study commissioned by the Indiana Department of Transportation (INDOT) in fall 2023 at the request of the Indiana General Assembly.
Expenditures: Lighter vehicle classes saw their share of cost responsibility decline between 2015 and 2024, while the heavier vehicle classes saw their responsibilities increase within this period. This change is explained by a diametric shift in expenditure type patterns between the two eras from construction-dominant to maintenance-dominant expenditures. In this context, it is worth noting that these expenditure types have different ratios of attributable costs to common costs.
Revenues: Fifty-two percent (52%) of all user and non-user revenues are generated at the state level, 36% at the federal level, and 13% at the local level. Vehicle Classes 2 and 9 still contribute the highest shares of revenues—42% and 22%, respectively. Vehicle Class 3 contributes 21% of the revenues, while all other vehicles contribute less than 10% each. Vehicle Class 13 contributes the lowest percentage share at 0.1%. Across the two eras (2015 vs. 2024), Class 2 vehicles saw their revenue share decline from 47% to 42%, but Vehicle Class 9 increased from 20% in the earlier study (2015) to 22% in the current study (2024). Vehicle Class 3 held steady at 21% in both periods, while Classes 5 and 6 saw marginal increases.
Equity Ratios: The equity ratio results follow a trend that is like those of past studies in Indiana and elsewhere. Generally, the lower vehicle classes are overpaying their share of cost responsibility and the higher vehicle classes are underpaying their share of cost responsibility. Notable shifts in equity ratios between the previous-era study and the current-era study were observed. Several lighter vehicle classes increased their equity ratios, while the heavier vehicles saw their equity ratios decline significantly between the two periods. EVs in Class 2 and Class 3 generally have lower equity ratios than their ICEV counterparts, a finding that is intuitive because EVs are associated with relatively higher damage but slightly lower, or similar, revenue contributions. For the forecast years (2030 and 2035), it was observed that EVs in Vehicle Classes 2 and 3 will be underpaying their share of the cost responsibility, while those in Classes 4 and 9 will be overpaying. The current EV fee that exists for these vehicles (if left unchanged) will not adequately cover their cost responsibility or recover the lost fuel tax revenues in 2030 and 2035.
Report Number
FHWA/IN/JTRP-2024/23
Keywords
cost allocation, highway revenue, highway expenditure, equity
SPR Number
4861
Performing Organization
Joint Transportation Research Program
Sponsoring Organization
Indiana Department of Transportation
Publisher Place
West Lafayette, Indiana
Date of this Version
2024
Technical Summary