Private equity investors The Carlyle Group have acquired United Road Services, a vehicle logistics company based in Romulus, Mich., from Charlesbank Capital Partners, the firm has announced.

United Road serves a client base of about 10,000 customers, including manufacturers, retailers, finance and leasing companies, rental agencies, auctions, web-based logistics firms and individuals.

Financial details of the transaction were not disclosed. Funds for the transaction came from the Carlyle Equity Fund II, a $2.4 billion fund that invests in middle-market companies.

Kathleen McCann will remain chief executive and chairman of United Road, while Mark Anderson will remain president and chief operating officer. The rest of the current management team will remain in place, according to the firm.

United Road expects to move 3.5 million vehicles this year compared to the 1.5 million the company moved in 2012, when the company was acquired by Charlesbank, McCann said.

"Our strategic growth platform was really turbocharged in late 2012 when we were acquired by Charlesbank," McCann said. "They provided the capital, support and encouragement to expand our reach and capabilities — both organically and through the acquisition of a major competitor, which gave us a deeper presence in the southeast and southwest U.S."

In late 2013, United Road acquired the auto transport division of Waggoners Trucking, which made the company the second-largest car hauler in the North America.

Mary Petrovich, a Carlyle operating executive and chairwoman of AxleTech International, will join the United Road board.

United Road and Charlesbank were represented by RBC Capital Markets and William Blair in this transaction. Carlyle was advised by Kirkland & Ellis as legal counsel and Ernst & Young as financial advisor.