Thinking "Korean engineers"? This must be a novel concept. Korean engineers are well known for their lack of creativity. There is absolutely nothing novel in the idea of battery powered buses. Regenerative braking is well known and has been used for decades. The only missing part is the good battery. And this is probably the weak point of these buses. Trolley buses are the way to go in places like Seoul, but local mafia (read Samsung, LG, ...) want the government to buy their batteries, so they arranged the deal with the "freindly" city-hall...

Sure there are bugs in the code. Any code has bugs. ANY car has bugs. I have the feeling that somebody is making a black PR campaign to create panic to humble Toyota.
Same was with swine flu - somebody wanted a panic to sell more medicines. There was also SARS several years before that.

How many people died or were injured because of the claimed Toyota software bugs? Give me a number.

You do not have to register it. The law can say that SW copyright will hold only if the binaries come with source or some way to get the source, much the same like GPL requires the source to be offered.

I had such ideas long time ago - for software and for art. Limited terms may work quite well for patents too.