ER diagram

A state-wide toll road system (MyStateTolls) allows users to buy an RF tag for use in paying tolls on their system. Each tag includes a unique tagID. In order to use the newly purchased tag a user must create a user account and add and activate the tag by ID. A user is either personal or commercial. The user registration system requires first and last name, street address, city, state, zip, and a bank account which will be charged for the tolls. The bank account is identified by nameOfBank, routingNumber, accountNumber, nameOnAccount, and permission to create reoccurring charges. Additionally a tag can be registered to only one vehicle. The vehicle must be identified by VIN, make, model, year, registrationID, stateOfRegistration, and class. The registration process allows for four classes of vehicle (passenger, commercial2axle, commercial4axle, commercialHeavy). A user can register more than one vehicle but each must have its own tag. 

Once the registration has been completed an initial balance is set on the MyStateTolls account. Additionally the user selects the level of charge to be drawn from the bank whenever the account balance is below the current charge level. The levelOfCharge can be either $15, $30, or $50, so the initial balance will also be one of these values. While driving the tag is read directly by the MyStateTolls system and the account charged with the appropriate road travel fee. At the time of the charge a toll is identified by tagID, location, timeStamp including date, vehicleClass, and amount charged. When the balance on a toll account drops below the level to pay the current charge, the levelOfCharge is deducted from the registered bank account and added to the Toll account balance so that the balance always remains positive. If a vehicle is disposed of, the tag must be made inactive. The tag is not transferrable to another vehicle or user.