Highway salt?

Interstate 80 (abbreviated I-80) is the second-longest Interstate Highway in the United States. It connects downtown San Francisco, California to Teaneck, New Jersey, a suburb of New York, just as the Lincoln Highway did in the years before the Interstate Highway System. The highway roughly traces some historically significant travel corridors, particularly in the Western U.S. These include the Oregon Trail in Nebraska and westward, the California Trail in Nevada and California, and the Union Pacific Transcontinental Railroad from western Nebraska to San Francisco.