Once you get your Interstate operating authority, you must register your authority with the Single State Registration System (SSRS). Essentially, you must pay each of the 38 participating states a fee for each vehicle you will operate in their state per year. Fees range $1.00 to $10.00 per vehicle.
If you are a moving company, you may not operate until you also publish your Tariff. You do not need to file your Interstate Tariff with the government but you must make it available to representatives of the US Surface Transportation Board and the public upon demand. Certain states such as New York State may require that you file your Tariff.
Make sure you are in compliance with apportionment (IRP), highway use taxes and fuel taxes (IFTA) before you commence operations. Movers are exempt from New York State highway use and fuel taxes but still need to comply with IFTA.