Mitsubishi wasn't invited.
Pretty much every major carmaker is working on autonomous driving systems in one capacity or another these days. But with every automaker taking a different approach, the results are widely varied, and there isn't any sort of standardization. But that might change, as it has just been announced that the big three Japanese carmakers, Toyota, Honda and Nissan, will be teaming up on autonomous driving systems; brought together at the behest of the Japanese government.
The big three will be joined by a number of universities and electronics companies in the autonomous driving consortium. The reason for this sudden push on the part of the Japanese government is simply that it feels the Germans and Americans have gotten too far into the lead with this technology, and it is feared that Japan will be left behind. The consortium will work to standardize equipment and software, as well as security and communications for the cars. The hope is that standardization will make further development both cheaper and easier. It certainly sounds like it would make the whole thing more viable.