625 ILCS 5/18c-4903

Each certificate or other proof of insurance or surety coverage shall have, as an implied term, that the insurance or surety coverage will remain in effect continuously until notice of cancellation is filed in accordance with Commission regulations, and that all motor vehicles operated by or under authority of the carrier will be covered, whether or not such vehicles have been reported to the insurance, surety, or other company. Filing proof of insurance with the Commission shall constitute acceptance of this implied term, and such acceptance may not thereafter be withdrawn except on withdrawal of all proof of insurance or surety coverage.