Self-driving cars could be a revolution for our cities. It's easy to see the market model moving from purchase to short-term rental, and to see most cars spending their days on the road, not stuck in parking lots. Right now parking represents one-third of the physical space in many of our cities. Self-driving cars could also, in theory, take up less space on roads. No more of that confusion you always face at exits, with drivers darting across multiple lanes after suddenly realizing they did indeed want to get off here. No more speed demons darting in and out, and fewer slowpokes making the speed demons even more dangerous -- it's relative speeds that create the most danger on our roads. That, and drivers impaired by age, drink, drugs, cell phones, hamburgers, hot coffee, ADD (squirrel!) and kids fighting in the back seat. But here's another market reality. I don't expect car companies like Toyota or Ford to simply give over control of their cars to some tech outfit. They will want to create their own technology, never mind the cost, and their influence on regulators could easily be used to keep tech-heavy rivals out of the market. If the tech companies want in, they may have to buy their way in. Now consider this: Ford had revenue of $136 billion last year. Google had revenue of $38 billion. When Google decided it needed to get into phone hardware to make headway in that market, it did not hesitate to buy Motorola Mobility, never mind the margin hit. A combined "Foogle" would have had earnings of $4 billion on revenue of $46 billion last quarter, by my calculation. So call me crazy. But just watch the technology evolve over the next few years. By this time in 2018 I may not sound so crazy. At the time of publication the author had positions in GOOG and F. Follow @DanaBlankenhorn This article is commentary by an independent contributor, separate from TheStreet's regular news coverage.