This updated manual prepares professional and prospective tractor-trailer drivers for the test that applicants must pass in order to receive a Commercial Driver"s License. The test, administered by the U.S. Department of Transportation, is required in all 50 states. Comprehensive coverage of both the written and driving tests is presented with specific answers and explanations for all questions and situations. This book is profusely illustrated with detailed diagrams and line art that demonstrate the proper procedures drivers need to master for their behind-the-wheel tests.