Get a package delivered to your house recently? There’s a good chance it traveled by truck to get there. Roughly 80 percent of all cargo in the United States is transported by the 7.1 million people who drive flatbed trailers, dry vans, and other heavy lifters for the country’s 1.3 million trucking companies. It’s an industry that’s forecast to grow 75 percent by 2026 — and it’s one Uber wants to dominate.