WASHINGTON—Freight carrier R+L Carriers Shared Services L.L.C. has asked the Labor Department for authorization to fund employee benefit risks through a captive insurer.

Under its proposal, which was filed last week, Wilmington, Ohio-based R+L would use Royal Assurance Inc., a captive licensed in 2008 in Arizona, to reinsure life, long-term disability and short-term disability risks insured by a Unum Group unit.

Royal Assurance is owned by members of the family that founded R+L, which has about 9,000 employees and a fleet of about 13,000 tractors and trailers.

R+L's application was filed by the Somerset, N.J., office of Aon Consulting.