Increasing electric vehicle (EV) adoption poses serious concerns about the long-term adequacy of highway revenues. This paper addresses not only the fuel tax revenue loss across all vehicle classes but also proposes alternative funding mechanisms to recover the loss. Data on average vehicle miles travelled per vehicle, fuel taxes, vehicle registrations, fuel efficiency and consumption are used. The case study location is Indiana, U.S., and analysis period is 20212035. The optimal annual fees to recover the loss for each battery EV class range from $241 (in 2021) to $342 (in 2035) for automobiles, $344 to $435 for light-duty trucks, $1246 to $1488 for buses, $969 to $1243 for single-unit trucks, $6192 to $7321 for combination trucks, and $26 to $35 for motorcycles. For the most likely scenario (5% EV market penetration (EVMP) for light-duty vehicles and 30% EVMP for medium-/heavy-duty vehicles), the statewide fuel tax revenue decreases by 21% from 2030 to 2035. The paper also discusses a vehicle-miles-travelled fee and a pay-as-you-charge fee. The study framework is designed to facilitate replication in other states, and the results can provide useful information for assessing the adequacy of the existing revenue models and efficacy of prospective mitigation measures.