Patents start from the filing date and last twenty years. Some of these things Google has could be several years old already, and it's unlikely that self drivin

Patents start from the filing date and last twenty years. Some of these things Google has could be several years old already, and it's unlikely that self driving cars will be on the road for at least another few years. Patenting something in 2010 that won't be profitable until 2020 means you've killed half the lifetime of the patent, so in that case a trade secret may be much better.