Zero-Emission Vehicles Act of 2020 This bill requires the Environmental Protection Agency (EPA) to establish a zero-emission passenger vehicle standard. Specifically, the bill sets a schedule for increasing the percentage of zero-emission vehicles a vehicle manufacturer delivers for sale, culminating in a requirement to sell only zero-emission vehicles from 2035 on. The bill also requires the EPA to establish a zero-emission vehicle credit program that approves one zero-emission vehicle credit for each zero-emission vehicle delivered for sale in the United States and partial credits for qualified electric vehicles based on the estimated proportion of the mileage driven on the battery. Manufacturers that fail to meet the minimum required percentage of zero-emission vehicle sales must submit to the EPA a quantity of zero-emission vehicle credits sufficient to offset the excess. Credits may also be sold, transferred, exchanged, or retired in certain circumstances. The bill imposes civil penalties for the failure to comply with zero-emission vehicle credit standards, with collected penalties being deposited into the Highway Trust Fund. After 2035, the EPA may issue injunctions on the manufacture of passenger vehicles other than zero-emission vehicles.