Tesla's long-delayed electric semi truck is finally going into production, good news for big fleets and bad news for small truckers, truck stops, and millions of drivers.

• The truck hauls heavy loads up to 500 miles and recharges most of its range in half an hour.
• Big fleets like Walmart, PepsiCo, and DHL are lining up, with one shipper group ordering 2,500 electric trucks.
• The math works because electricity costs a fraction of diesel per mile, and diesel just topped $8 a gallon in parts of California.
• Small trucking firms lose out: they can't afford to build their own charging depots, which points to mergers and consolidation.
• Self-driving features are coming to the truck, putting pressure on millions of professional driving jobs.

Outlook: Expect more fleet orders and a squeeze on small truckers, with the real test being whether 500 miles between charges is enough for long-haul routes.