Tesla Inc. CEO Elon Musk introduced the Semi electric truck Thursday. Some of the country’s biggest trucking fleets are among Tesla Inc.’s first customers for its all-electric big rig. J.B. Hunt Transport Services Inc. and Wal-Mart Stores Inc., which operate thousands of trucks, said Friday they had reserved Tesla’s truck, which Chief Executive Elon Musk revealed at an event in Hawthorne, Calif., on Thursday. The first highway-ready vehicles aren’t due out until 2019, but the company is taking $5,000 deposits. Truck leasing and fleet management company Ryder System Inc. R -4.34% “is in the process of placing its initial order for a fleet of Tesla semi-trucks,” Dennis Cooke, the company’s president of global fleet management solutions, said in an email. Ryder declined to specify the size of the order. The Semi is designed to run up to 500 miles on a single charge, and incorporates Tesla’s semiautonomous driving system, […]