The Pep Boys chain of automotive parts and service outlets has announced the introduction of a comprehensive used-car certification program that will cover all brands. The program is designed to provide used-car buyers with an assurance that a used vehicle is mechanically and operationally sound. Both commercial and consumer markets will be able to use the certification. Currently, a pilot certification program is operating in 11 stores, with plans to expand to 200 stores by the end of May. Last year, more than 40 million used vehicles were sold in the United States, a market valued at $336 billion dollars.