Decree affirmed. The Industrial Accident Board found (a) that the claimant, Dustrude, the operator of a tractor-drawn trailer, was an employee of the uninsured “owner-operator,” Leighton; and (b) that Leighton was, as to the insured carrier and trailer owner, Chicago Express, Inc., an independent contractor under a “trip lease” arrangement. See American Trucking Assns. Inc. v. United States, 344 U. S. 298, 302-306. The findings were not without evidential support and were not tainted by error of law. Van Bibber’s Case, 343 Mass. 443, 447. They are determinative of the ease. Costs of this appeal may be allowed by the single justice under G. L. c. 152, § 11A.