If you apply for authority to be an Interstate carrier then you will need to obtain liability and cargo insurance. The usual trucking insurance amounts are $100,000 cargo liability and $1,000,000 for liability.
When you apply through DOTAuthority.com, they will help you find a broker that specializes in commercial transportation insurance if you don’t already have an insurance broker. They do recommend, however, that you look into insurance rates before you file your application as your application fee is non-refundable.
Common Carriers must also file evidence of a $10,000 cargo insurance policy. Freight brokers must file evidence of a surety bond/trust fund.