After the Road Repair and Accountability Actof 2017 (Senate Bill 1) was passed, transportation revenue funding in California was bolstered by numerous fees including gasoline and diesel taxes, as well as an annual registration fee exclusively for zero-emission vehicles(ZEVs). We assess theability of the ZEV registration fee to provide adequate funding in the future, how the registration fees affect the sales of ZEVs in California, and alternative funding mechanisms instead of the registration fee. We find that the registration fee is not a sustainable mechanism to provide adequate funding as California transitions towards ZEVs. Additionally, the fee detracts from the market adoption of ZEV technologies by as much as a 20% decrease in new ZEV sales. Lastly, we examine alternative funding mechanismsinclude a fuel tax for hydrogen and electricity, as well as a road user charge (RUC). We find that a ZEV exclusive RUC is the mostpromising alternative to the ZEV registration fee.