Elon Musk is pushing lawmakers to help clear a path for driverless vehicles, according to people familiar with the matter, part of a broader effort behind the scenes to lobby for a key priority of Tesla Inc.In recent weeks, Musk and people who work for him have been calling members of Congress directly to gather support, said the people, who asked not to be named because the discussions are private. He has also been weighing in on revisions of a bill introduced on May 15 that would begin setting...