Electric Credit Access Ready at Sale Act of 2018 or the Electric CARS Act of 2018 This bill amends the Internal Revenue Code to modify and extend several tax credits related to electric cars. The bill extends the tax credit for new qualified plug-in electric drive motor vehicles through 2028. In addition, the bill modifies the credit to: remove the limitation on the number of vehicles per manufacturer that are eligible for the credit, allow a taxpayer to assign the credit to a financing entity, and allow an unused credit to be carried forward for five years. The bill also extends through 2028 the tax credits for: (1) alternative fuel vehicle refueling property, and (2) alternative motor vehicles.