GM: you won't buy self-driving cars at dealerships for a while

Do you dream of having a self-driving car in your driveway, ready to whisk you away at a moment's notice? You might have to keep dreaming for a while. GM president Dan Ammann tells Business Insider that he doesn't expect autonomous vehicles at dealerships until sometime "much farther in the future." You're more likely to see them used in ridesharing fleets at first, he says. GM clearly has a vested interest in that business between its partnership with Lyft and its own car-sharing efforts, but Ammann has some practical reasons for tamping down expectations.

Much of it has to do with pure geography, he explains. It's relatively easy to have self-driving cars navigate the relatively small and orderly world of a city, but it's another for them to venture across the country. They'd have to consider a much larger area with varying terrain and weather conditions.

We'd add that varying signs and rules of the road could complicate matters. And there's the question of whether or not you'd need a personal car -- if you can regularly summon a robotic ride within a few minutes, why buy your own and go through all the hassle of maintaining it? Companies like Lyft and Uber might be highly optimistic about a future of widespread autonomous ridesharing, but their vision has some basis in logic.